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FAQs on the Molly Compatibility

Related Articles: Mollies, & Poeciliids: Guppies, Platies, Swordtails, Mollies by Neale Monks, Livebearing Fishes by Bob Fenner,

Related FAQs: Mollies 1, Mollies 2, Molly Identification FAQs, Molly Behavior FAQs, Molly Selection FAQs, Molly System FAQs, Molly Feeding FAQs, Molly Disease FAQs, Molly Reproduction FAQs, Livebearers, Guppies, Platies, Swordtails

With warm-water, soft-acidic condition livestock
With other hard-alkaline and brackish water livestock
Mostly yes.

Hyper-Aggressive Male Molly     1/5/17
<Hello Caitlin,>
I've been keeping and raising molly fish for years now, but suddenly two weeks ago the two male mollies I had in my tank started displaying incredibly aggressive behavior towards each other and my (at the time) lone female molly in the tank. She ended up getting pregnant (as mollies do) and the day she gave birth to four or five fry, the two males began fighting each other pretty viciously. Before the fry were born, neither male had ever shown any aggression to one another or any other fish- they were both born in the tank, have lived there in peace for almost three years now- so
it was a shock to see them behaving so out of the ordinary. After reading up about their behavior thanks to the amazing information your website was able to provide, I decided to add in more female mollies (something I was and am reluctant to do as I will likely be moving sometime soon, and I didn't want to have to move so many fish over four hours up the road) but when I did add the new females in, a larger Dalmatian molly and two smaller gold dusts, one of the male mollies started very viciously attacking the two smaller gold dust mollies to the point where I was sure he was going to
kill them.
<Understood. When adding extra fish to the system, there's a "getting to know you" period where existing fish jostle for position with the newcomers, establishing a pecking order. It can help to remove pre-existing territorial Mollies, rearrange rocks and plants so the tank looks new, introduce the new Mollies, turn out the lights, and an hour later, add the original Mollies. With luck, the tank will look new to all the Mollies, the lights being out will trick them into sleepy time, and by the next morning, peace will reign. Doesn't always work, but it often does.>
Taking more advice from WWM, I put him in an emergency backup tank for three days to try and get him to calm down (the only breeding box I have is being used for the recent fry), but when he was reintroduced to the tank he immediately began attacking the two smaller females again and fighting with the other male. I pulled him back out into timeout for the safety of all involved, but I'm really not sure what else I can do to keep him from attacking the two gold dust females.
<See above; if that fails, can you rehome him?>
He completely ignores the other two bigger female mollies in the tank, and when he attacks the gold dusts it doesn't seem to be with any mating intent; he often pins one against the bottom or side of the tank and, for lack of a description, seems to spasm and body slam them into the gravel and tank walls or bites at their sides and tails when they flinch or try
and run away, though he never seems to be trying to mate with them because his anal fin never moves to "do the deed", as it were. The tank itself is 33 gallons, with a pH level of 7.5, nitrite and nitrate at slightly above zero (though I'll be doing a water change and cleaning almost immediately after I send this question), with no traces of chlorine and fairly high hardness and alkalinity. There are three other fish in my tank: one Glass Catfish, one Zebra Danio (both of which are only alone because I received the glass catfish from a neighbor who was moving and only had the one left,
and the zebra Danio is the last survivor of five- they're actually almost ten years old, now), and one Chinese Algae Eater (who, after reading up on them on your website, I may not have for much longer. Didn't do my research on that one). Do you have any other advice for calming a male molly's aggression, or any ideas why both males so suddenly became aggressive? I'm thinking of upping the female-to-male ratio to 3:1, as it likely should be, but I don't want to add more females into the tank if he's going to ignore them, like the others, and just focus on the two gold dusts again. The
other male in my tank displays none of the killing-aggression of the one I removed, and everything calmed down very quickly after I pulled out the problem one. I really wouldn't want to get rid of him, but I'd like to know if there's any hope of returning him to my main tank or if I should go shopping for another. Thank you for any help you can provide! -- Cj
<Hope this helps, Neale.>

My fish is attacking other fish; child        2/18/16
The one that is attacking the fish is a boy and the ones it's attacking are girls
<? Separate them. Bob Fenner>
Re: My fish is attacking other fish       2/18/16

But it could be mating they are mollies just saying
<Search, READ on WWM re Molly Behavior, Reproduction and Stocking. B>

Platy and Molly community tank issues     11/21/14
I have a 10 gallon community tank with 2 platy females, 1 platy male, 2 molly females, and 1 molly male. (learned the hard way about having too many males together).
<Indeed! A good tip: with non-sailfin Mollies and Platies, just keep females. They look the same as the males, but aggression will be minimal.>
My issue is that my male platy who is a Mickey Mouse platy doesn't seem to eat much.
<Do review "Wasting Disease" in livebearers. Typically caused by a bacterial infection, such as Mycobacteria. Fairly common, and the affected fish stops eating, becomes lethargic, gets thinner, and eventually dies.
Adding a little salt to livebearer tanks is cheap and easy way to perk them up; try 1-2 teaspoons per US gallon. This won't cure bacterial infections but may help a slightly infected fish feel better and maybe heal itself under its own steam. Otherwise, antibiotics may help in some situations, though Mycobacteria infections are essentially impossible to cure.>
He is very active but during feeding time he hangs out at the bottom.
<Is he being bullied at feeding time?>
Same thing with my Balloon molly female. My male molly normally eats anything and everything I put into the tank. I'm worried about my Mickey and balloon not getting enough food and then my Dalmatian molly getting over fed. Is there a way to balance out how much they each get and to make sure they eat?
<Yes. Two approaches. One is get floating feeding rings (or make your own from plastic of some sort). Put flake inside the feeding rings. These trap flake in certain areas. With luck, you'll find the bullying fish occupied at one ring, leaving the quieter fish to use another. Second approach is to use sinking algae wafers. Break these into halves or quarters, offering 1-2 wafers per feeding session, once per day for a 10 gallon tank. As the wafers soften the Platies and Mollies will peck at them, and because they take hours to fall apart, there's lots of time for all fish to have something to eat.>
Also one of my female platies who is a bumblebee like to follow my Dalmatian molly around (basically never leaves him alone, no nipping but always at his side). Is that normal?
<Yes. Female livebearers are sociable in the wild, not quite schooling fish but certainly appreciating company. Since none of the livebearers we keep are pure species (i.e., they're all hybrids of one sort or another) it's
probable their idea of what "they are" is pretty mixed up, too. Cheers, Neale.>
Re: Platy and Molly community tank issues      11/21/14

Molly Issues. I just looked at my tank and I noticed that my balloon molly female (white in color) has a dark black line spot
<A line or a spot?>
near her tail and the other side has the same thing but a bit lighter. What could that be?
<Honestly, no idea at all. Your description doesn't really provide any clues. Any chance of a photo? In the meantime, review aquarium conditions, look for signs of damage and/or subsequent infection, and act accordingly.
Cheers, Neale.>

Angel fish with mollies     10/20/14
Hello Crew, hope all is going well. I have an innovative marine nuvo 38 gallon which is 24 inches along and 19 high. I have 1 male black molly along with 2 females as well as 6 sterbai corries. I would like to use an
angel fish a "center piece" so to speak; and I was wondering if an angel would be compatible in this smaller tank.
<Singleton Angels (farmed Angels, anyway) can be kept in tanks from 20 gallons upwards, provided there's a good 30 cm/12 inches of water depth. So you should be fine, assuming the water chemistry suits all the species
If so, do different types of angels have different temperaments so I could get a less aggressive one?
<There is some variation among Angelfish varieties, with all-black Angels (in the past, anyway) identified as peculiarly aggressive, while some of the more inbred forms (such as Koi Angels) grow more slowly and tend to be more easily picked on than other sorts. In short: avoid keeping random twos or threes as these often devolve into one bully and the rest mere victims.
Also avoid the more inbred varieties. Silver Angels, Marbled Angels and Golden Angels, as well as mishmash crossbreeds of these, tend to be pretty reliable. Singletons are fine, mated pairs are fine, and groups of six or
more usually work out some sort of modus vivendi given enough space.
Unfortunately, you cannot sex Angels, so getting a pair means either buying a mated pair (expensive!) or rearing six and allowing them to pair off themselves (but even then, Angels occasionally pair off in same-sex pairs).>
And lastly is it OK to keep a single angel without a partner or others of the same sex?
<Absolutely, at least with farmed Angels. Altum Angels, wild Scalare Angels and so on are probably best kept as schools.>
Thank you for your help
<Most welcome, Neale.>
Re: Angel fish with mollies     10/21/14

Thank you for the advice. I have one more question, please. The water pH in my area is about 8.3.
<Sounds like liquid rock. Presumably the water is very hard. Mollies will be happy!>
If I did a slow and correct acclimation on an angel would it be safe living in that pH?
<Possibly, but I wouldn't bank on it. The pH is somewhat less important than the hardness. Above 20 degrees dKH hardness Angels may struggle to thrive. So get your hardness tested before doing anything else.>
Are there some breeds that would adapt to the higher pH easier than others?
<Ideally, get locally bred ones; have seen some hobbyists breed their Angels in liquid rock, and these will be ideally suited to your aquarium.
Farmed ones shipped over from Southeast Asia are more likely to have been reared in soft water. Contact your local/city fish club. Angelfish are invariably a popular species for breeding, and consequently shouldn't be
difficult to source locally.>
Thank you.
<Most welcome, Neale.>
Re: Angel fish with mollies     10/21/14

Thank you again. Please tell me what dh hardness is, and I assume there is a test kit for it?
<It's called "German Hardness Scale" measured in degrees dKH. It measures General Hardness (sometimes called GH) rather than Carbonate Hardness (which is measured in degrees KH). Yes, there are many general hardness kits. Some give their results in degrees dKH, others in mg/l equivalents of either calcium oxide or calcium carbonate. Do read: http://www.wetwebmedia.com/fwsubwebindex/fwh2oquality.htm
Essentially, if the water is soft to moderately hard, Angels are fine; if it's hard to very hard, they're not a good choice.>
Also, if the angel is surviving in the LFS at a higher pH it should be OK I assume unless it hasn't been in the tank that long and can be in bad health without symptoms?
<No. A fish lasting a few weeks in a tropical fish shop isn't the same as a fish living the next 10 years in your home aquarium. Check your water chemistry, then decide. Better still, find a local keeper/breeder and get
some Angels used to your water, if such exist.>
<Cheers, Neale.>

Molly; repro./comp.      8/5/14
After returning home from a short trip, noticed the new Molly we just got had babies!! She's in a tank with a barb(?), I think. We've had that fish for a couple of years. Anyways....there were 5, down to 3 now. Moved the barb to his own tank then noticed the Molly seemed to be wanting to eat the babies so put her with the barb. Now what?? Can they all go back together once the babies get a big older and bigger?
<Ah yes... a quarter inch or more in length should do it>
<Welcome. Bob Fenner>
Re: Molly     8/5/14

Awesome! Thank you for your quick reply!!
<Cheers, BobF>

Freshwater Angelfish and mollies, comp.      6/1/13
If a single farmed angelfish is raised in hard alkaline water, could that angelfish co-exist with a few female mollies in a large tank?
<Yes, with the smaller (shortfin rather than sailfin) Molly varieties.>
Mollies like hard alkaline water.
<Correct, and good water quality too.>
I would think that the angelfish may harass the docile female mollies or would be attacked by aggressive male mollies.
<Adult male Mollies can harass community fish it is true, but adult Angels should be big enough to hold their own, assuming the tank is reasonably large, say, 30+ gallons.>
Or are mollies always better of brackish?
<A slippery question. Mollies are almost always healthy in brackish water, whereas some specimens are sensitive, even disease-prone, in freshwater -- so in that sense brackish is best. But it isn't essential to keep them in brackish, and provided water quality is good (note: this includes nitrate, not just ammonia and nitrite) then Mollies can and do just fine in freshwater.>
Thank you
<Welcome, Neale.>
Re: Freshwater Angelfish and mollies     6/1/13

Sorry I forgot to ask if mollies would be fin nippers?? Thanks
<Not normally, but some species are (e.g., Liberty Mollies) so you have to be careful. In any case, mixing pretty much any boisterous fish, like a Molly, with veil-tail Angels or any other fish with unnaturally long fins is asking for trouble. Cheers, Neale.>
Re: Freshwater Angelfish and mollies     6/1/13
I made a mistake with the mollies. The one angelfish is a superveil and he is a bully, he doesn't care about the three female mollies.
<Ah, that's good. Some Angelfish strains are said to be particularly aggressive, the all-black one for example, but in any case, like you I've seen some Angels that were thugs, while others were good as gold. Like any cichlid, they have the potential to surprise!>
They may go after his fins if not now later.
<Possibly. But you can certainly wait and see -- fin-nipping isn't lethal, and evidence for it will appear long before there's a risk of Finrot or similar.>
So I better put them in the 10 gallon tonight and take them back tomorrow.
Thank you
<Seems you have a plan! Veil-tail Angels are best kept alone or with definite non-nippers, such as Corydoras catfish. Cheers, Neale.>

Molly's and Betta's    6/18/12
Hi there!  I am a long time fish keeper now, I breed mutt Molly's (mixed breeds) for my local fish store.
<Mmm, mixed species?... am not a fan>
I breed some really neat looking fish!  I have my adults in a 35 gallon tank and the females get moved to a 25 gallon baby tank to have her babies.
  Recently I came across this beautiful crowned Betta and his little female at my local fish store.  I had to get them! (we did a trade).   I was told "they will hunt and eat the babies so don't put them in the baby tank, but they should be fine with the adult molly's." 
<Actually; not really... Betta splendens prefers warmer water than Mollienesia; the latter prefer more hard, alkaline and brackish water>
So I took them.  All seems to be going well but I question if this will last?
<Define your temporal (time) frame... In mine, not long or well, no>
 My tank is very well planted and has lots of hiding spots, they have been in there for 3 days no fighting or signs of nipping.
35 gallon adult tank
-2 silver molly's
-1 Dalmatian molly
-2 gold dust molly's
-2 Betta
-2 baby mutt Molly's (half inch)
(At any given time there are usually at least two fish in the other tank so typically there are only 7 fish in the 35g tank at one time)
Thanks in advance Jacquie.
<Success defines itself. If you're happy... Bob Fenner>

Creamsicle Lyretail Molly Trouble and a salt question. Livestock of differing water quality needs tog.     6/13/12
Hello!  Thank you for such an informative site.  I have spent hours and hours reading the wealth of knowledge it provides...yet I still feel unsure about my situation.  I apologize in advance for possible info-overload, but I'd rather err on the side of too much than not enough.  My FIL gifted my 2 year-old daughter a 20 gallon aquarium for her birthday (at my suggestion; I was excited about it also, as well as willing to put forth the effort it requires).  At the time, my idea of keeping fish included water, a bowl, and some fish...little did I know!  Since then, 3 months ago, we have acquired: 3 Neon Tetras (unsure of sex),
<Mmm, these really need different water quality than the livebearers you're keeping... soft/er, more tropical...>

1 male Albino Bushy Nose Pleco, 1 male Lemon Cobra Guppy, 3 male Harlequin Sailfin Mollies, 1 female Creamsicle Lyretail Molly, 1 female Dalmatian Lyretail Molly, 1 male Mickey Mouse Platy, 1 male Sunburst Wagtail Platy, 1 female Red Platy (just died), 2 African Dwarf Frogs, and a single Ghost Shrimp who has survived this
whole time, amazingly enough!  I also have two varieties of live plants: Hygrophila and Cyperus;
<Cyperus? A sedge? Is this emersed?>
both have done really well.  Just this week, I began half-dosing the tank with Aqueon Plant Food (10mL/20 g).  In the beginning we lost a black Platy, and I didn't think twice about it at the time; I thought that fish just died...ce la vie.  I don't remember it having any spots/fungus/weird behavior indicating any of the issues listed on the Disease Troubleshooting page; however, I also did not know that it is best to quarantine new fish. 
We introduced 3 batches of fish within one week of getting the tank set up. 
<Uncycled risks...>

Fast forward to present.  This past weekend we were out of town for two days to come back and discover a tiny red female platy...obviously, the Red Platy had had babies, and we didn't even know she was pregnant.  Having the three females in there was a mistake; we wanted to only have males (is this even a good idea?).
<Can be>
 The reason being, I did not want to have to deal with off-loading baby fish...repeatedly.  Plus, I'm kind of half and half on how I feel about just letting the females have babies and it being a free for all for snack time.  *bag over head*  ...not sure how the experts feel on this?
<A mix as well>
 Yesterday, the female Red Platy died.  She had been sitting on the bottom of the tank, and I read and read and researched and couldn't come to a conclusion as to why she was doing this.  I ran out immediately and got a water test kit (yep, learned that I needed one of those 3 months too late). 
Today I tested the water before and after the cleaning/gravel suction; I replace 25% of the water once a week.
 I add 10mL of Aqueon Water Conditioner each time I do this.  These were my
readings after I changed the water: GH 30, KH 120-180, pH 7.5-8.0, NO2 0, NO3 20. 
<Keep Nitrate no higher>
The temp is always about 78 degrees F; today was the same.  I don't keep a fish heater in the tank, as we live in Arizona and I keep the house pretty warm...free heat!  These readings weren't much different from the before reading...the only difference being the NO3, which was 40 before the cleaning. 
<Too high>
According to the test directions, my GH is too high.
<Mmm, I wouldn't likely "fool with it/this">
  I didn't see the recommended solution
<Blending in some water (RO likely) w/ less mineral content>
 to that at my local pet store, however (API Electro-Right).  Also, is the pH okay, or does it need to come down a bit?  It seems fine for some of the fish, and too high for the others.
<Is high for the Neons, but not for all else>
I have since learned from all my reading that I have overstocked, and that I have mixed Mollies with other types of fish, when they should be by themselves.  I also have learned that by not having enough females to males, I was creating problems with chasing them to death; I'm still not sure why the female Red Platy died.  All of the fish chase each other in there; they always have (the guppy, especially, likes to chase the big Lyretails).  I never see them nipping, though.  I do not plan on restocking as fish die, and I hope to create a happy, safe environment for the ones I have...as best I can.  I have also learned that the frogs prefer to be alone, but these actually don't bother each other (seemingly).
 <Ah yes>
The problem I'm having with the female Creamsicle Lyretail Molly is that she has started floating upright, midtank, in the water.  She looks, occasionally, like she is shivering.
<The metabolite concentration... as "windowed" by your NO3 testing/results... poisoned by their own wastes. Very common>

 I have noticed that on her pectoral and caudal fins, which are fairly transparent, she has these whitish looking spots.  They are fairly bigger than grains of salt, leading me to believe it's not Ick,
<Maybe... though could "just be body mucus clumps"... reaction to water quality issue/s>
 and they aren't in clusters...just a handful all together.  She seems to swim fine when she isn't doing the vertical-hover-shiver thing, and she eats normally.  I noticed this morning that she has some bumps on her head...also fairly bigger than grains of salt.  There's nothing on her body that looks different or "wrong"...no white specs or anything.  I went to the store today with the knowledge from this site and hoped to have the "fish specialist" at my local pet store help me, but that turned out to be a fail.  I did end up spending a good hour perusing the medicines, and ended up coming home with Tetra Lifeguard All-In-One Treatment, but I'm unsure if it what I should put in my tank...?  
<I wouldn't>
Any ideas on what could be bothering her?
<The environment
... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm
and the linked files above if still unclear>
  I just worry (now that I know better) about something infiltrating the whole tank and hurting more fish. I know (now) that mollies do much better in a brackish environment.
<Ah yes>
  My other question about that is, can I introduce marine salt, considering the other cohabitants and plants? 
<... Mmm, best for you to spend the time "looking up" such information... the Neons "don't like" salts... neither Hymenochirus... the livebearers are fine w/ a modicum...>
If so, do I introduce it slowly, or just go all-in and follow the directions on the box of API Aquarium Salt...which says 1 rounded tablespoon per 5 gallons of water (so 4 rounded tablespoons)?
<... you'll need to investigate, likely move the non-salt livestock elsewhere ahead of the addition>
Because I do have an overstocked tank, would more hiding places be encouraged?
<Mmm, yes>
 Currently, I have a piece of driftwood (fake) that takes up the length and height of the tank (but is narrow) to provide some good shelter, as well as the two types of plants I have now (the Cyperus, of which, has set out about a dozen runners that have sprouted up quite nicely, so I bunched them all in the same corner) and a small pirate ship (at my daughter's request...*smile*).  My idea was to add some plants to grow on the surface of the tank; would this be good?
<Yes; a/my fave Ceratopteris...>
 If so, what kind would you recommend based on my current tank environment?
I do thank you for your time. 
<You have two great requisite traits for being successful (not just w/ pet fish); a curious mind and desire to improve situations... Read a bit and do write back if you are unsure of a plan... to separate (have two systems) and modify water quality to suit the life in your charge. Bob Fenner>

Will adult Mollies eat Baby Guppies?
<Yes. Cheers, Neale.> 

Pregnant Molly, beh./sys.   3/3/12
Hi, my name is Alejandro. I recently bought two black female molly fish and put them in a 10 gallon tank.
<Really need more room than this Alejandro... too small a volume to keep stable; allow for movement, diffuse territoriality. Please read here:

Everything seemed just fine until I noticed that one of the female mollies may be pregnant. The thing is that the pregnant molly keeps attacking the other one, who is a little smaller.
<Ah, yes. Common behavior>
Today I noticed that the little one keeps hiding over the floating plants on the top of the tank. I thought that this may be due to the ammonia or nitrite levels in the water (I don't have any way to measure them, so I just guessed), so I changed half of the water in the tank.
 Still, the little molly keeps hiding, since the pregnant molly keeps chasing it all around the tank. I've looked on your website but it seems that the male mollies are the territorial ones. Is this territorial behavior normal in pregnant mollies? Thank you
<This behavior is natural... You should separate these fish, look to getting a larger system. Bob Fenner>

Balloon Molly   3/1/12
Hi, I hope you can help me. I have a 40gallon aquarium with 3 balloon mollies, 2albino bottom feeders, and a small Pleco. I do 4-5day 20% water changes, the temperature of my water heater is on 75f, all the PH levels and ammonia levels are okay (as I even went to the pet store to get them to check over it) and I'm concerned over my female black balloon molly. I purchased her around 6 weeks ago, and she started showing signs of pregnancy about a week after I got her. She is still pregnant and has not given birth yet. She is continuously getting bigger, and shows clear signs of stretching on her gills. Why hasn't she given birth yet? I did have a Chinese fighting fish, but had to take him back to the store, as he was constantly chasing the black balloon Molly, this was over a week ago, I would have thought she would feel comfortable enough by now to lay? Also one other thing, my orange balloon Molly who I have had since purchasing the tank (at Christmas) he has began to develop a small outline of black on the edge of his tail fin. It is not on the top fin, only the back. I have done my research into fin rot, but this doesn't seem to be the case...
Thank you
<Hello Melissa. Start by reading:
Mollies rarely do well in mixed community tanks, and while you say things like "pH levels are fine" that means nothing at all, and since Mollies need hard, ideally brackish, water, it's unlikely you have optimal conditions for Mollies if you're keeping them with soft water fish such as South American catfish. Furthermore, your tank is way overstocked, or will be eventually, given that a single Plec (assuming this is Pterygoplichthys sp.) requires at least 55 gallons when mature, and generic "algae eaters" (Gyrinocheilus aymonieri) at least as much (and two adults will squabble even in 200 gallons!). So read the linked articles, and see what you're doing wrong. Mollies are easily stressed, and in freshwater are acutely sensitive to nitrate above 20 mg/l (obviously ammonia and nitrite must be zero). They do much better (and are easier to keep) in slightly brackish water, but adding enough salt to help would stress, even kill, freshwater fish such as Plecs and Gyrinocheilus. So adding pointless amounts of aquarium salt like "one teaspoon per gallon" isn't what's meant by brackish water, which requires marine aquarium salt at upwards of 5-6 grammes/litre (0.6-0.8 oz/US gal.). Finally, fancy Mollies do thrive on warmth, not less than 25 C/77 F. Cheers, Neale.>

Molly aggression 1/23/12
I have a 10gallon tank with a Dalmatian Molly, Gold Dust Molly, and a Silver molly.
<Tank is small for these fish.>
They are all females. The Gold Dust Molly will not leave the Silver molly alone.
<Mollies can be aggressive in confined quarters and do better in larger numbers where the aggression is dispersed. They really aren't a good beginner fish because of their specific water requirements and the issues like the one you describe. Read here with the related FAQs in the top tray- http://www.wetwebmedia.com/fwsubwebindex/mollies.htm>
The first couple of days after I introduced them they did their own thing.
<Getting adjusted>
Now the Gold Dust Molly is constantly chasing both of the others. The lady at the pet store told me the Gold Dust was a male but after asking how to tell the difference between males and females I've realized she is a female and is possibly pregnant. Her belly is pretty big.
<May well be pregnant but the belly being large could also be bloating.
Please do read about the dietary requirements of this fish.>
Any idea why she is being so aggressive. I think she is stressing out my Silver Molly, she seems to be hiding a lot more than usual. The Dalmatian will follow her (silver molly) around sometimes too but not near as much as the gold one.
<Do read where referred and rectify the tank size/water parameters accordingly.
Thanks for your help! <Most welcome! Sugam>
Re: Molly aggression 1/23/12

Thank your for the reply.
We test the water often and keep it clean and brackish.
<Meaning what? Numbers are helpful to me.>
We are going to move them to a 20gallon tall tank as soon as we can.
<A bad choice'¦ 20 gallon "tall" tanks are not good for most fish/fishkeepers. In any case, these Mollies need tank length, not depth.>
I have read up on the diet.  We have been feeding them veggie flakes and regular fresh water flakes every other day. A lot of websites say to feed them blood worms. Do you agree with this?
<Sure, once in a while. But Mollies feed mostly on algae in the wild; respect this.>
Also my silver molly gets a purple discoloration behind her gills sometimes, is this a sign of stress?
<Can be; or at least, obviously reddish gill filaments and/or gill covers can suggest damage/irritation to the gills. Cheers, Neale.>
Re: re: Molly aggression 1/23/12

We will get a long one instead.
<Good. Mollies really need tanks above 90 cm/3 ft in length. Volume isn't critical, but really, you want 30+ gallons, give or take. Male Mollies are aggressive, and females can get rather big (15 cm/6 inches in some cases). So do plan ahead.>
When I tested the water last night the ammonia was 0, nitrite 0, nitrate 5.0. pH 8.0
<Sounds fine. Cheers, Neale.>

Balloon molly getting picked on!  1/21/12
I have a 20 gallon tank that's not that new but not that old I've recently had the water tested at my local fish store and they said the water is perfect!
<So it's hard, alkaline, warm, and slightly brackish?>
My problem is that I started out with 2 balloon mollies one male one female and I keep hearing that you need more then one female to every male.... So I had added another female to the mix.. As soon as I integrated her to the tank she started picking on my original female molly (whitie).
<Mollies aren't sociable and your aquarium is too small for them. They do best in big groups in spacious tanks. Kept in twos and threes they often become aggressive, males especially, but the females sometimes as well. Without swimming space, they can't easily keep away from each other when tempers flare. So completely unsurprisingly, yours aren't getting along.>
I contacted the store they said its a dominance issue and I could bring her back for another fish. I brought home a different female and she started doing the same thing she's actually picking on her worse then the other molly. Is there a reason why these new females keep picking on my original female?
<Well, Balloon Mollies are deformed and crippled by their bent spines and distorted swim bladders, so like adding a Chihuahua to a pack of wolves, the "man-made" variety simply can't hold its own when it comes to social behaviours and assertiveness.>
or am I just doomed to have one male and one female balloon molly in this tank? Also when the new females pick on the original the one male molly seems to not allow it.. My original female is also very pregnant and ready to birth her fry any day now.
Thank you'¦.May
<Most welcome. Do read:
Mollies aren't easy to keep and most people starting with Mollies keep them wrong. Read, review, and act accordingly. Cheers, Neale.>

A Newby~ Question about fish compatibility for stocking a tank, and population control   1/8/12
I have read about Mollies being unsocial, but the group I have now of two balloon males and 4 females is very peaceful.  They hang together too at night. 
<Cool. But if you peruse the Molly FAQ pages here at WWM, you'll see we get a lot of messages about aggressive Mollies, usually, but not always, the males. Just because things have worked out so far, don't assume that they will indefinitely, and keep an eye out for fish hiding away a lot while another becomes more outgoing as if "in charge".>
The first male was super timid and hid all of the time until I introduced the other fish to the aquarium.  Now he's always out and about.
I returned/exchanged two aggressive females, and then I returned/exchanged two aggressive males, and came up with this final ratio of the two males and four females that are working out well together.
<Real good.>
My second male is more assertive than the first, but they are coexisting very peacefully and he's definitely not high on a scale of assertiveness. 
I have two shy female fish and two more outgoing one's, but thankfully no bratty one's like the one's I returned before.
I'd recommend anyone wanting to have these in their tank taking advantage of the store's return policy to find the perfect fish.  You can also observe how they're behaving towards their many tank mates in the store. 
Each one has it's own type or temperament.  And funny, the very most assertive male that I returned was just a baby still!!!!  They must be born with their tendencies.
<Very likely true. If you think about the life of a Molly in the wild, it's pretty hard for the males. Females only mate with the fittest males (in the Darwinian sense) so any male that can't assert himself is doomed to not pass on his genes. The big sail fin on the males costs energy to grow, and at the same time, the males are smaller than the females, so more likely to be eaten. That modified anal fin of their surely reduces their swimming ability somewhat too. All in all, male Mollies have shorter, tougher lives than the females, and that explains their sense of urgency when it comes to mating. Studies on Guppies are even more alarming (for as males, anyway) because it seems females actively seek males with brighter colours because there y're likely to get eaten, and therefore the ones who had to be smart and fast simply to live long enough to reach sexual maturity!>
They're entertaining, always munching, and some of them even lick the glass, which is amusing.  The balloon males are bulky and appear to be interested in the females but not "on a sole mission to populate," as the two regular style males that I returned because they were so aggressive were.
I am just sharing this for info on my own experience so far with this interesting, very colorful little fish, and for anyone with a large enough tank who is thinking of getting some, I'd highly recommend them.
<Agreed. As I've said many times before, Mollies are outstanding fish -- do check out Liberty Mollies some time -- but their very specific needs really do mean, I believe, that they're best given a tank of their own.>
Thanks again,
<Cheers, Neale.>
Re: A Newby~ Question about fish compatibility for stocking a tank, and population control   1/8/12

Thank you Neil.  Yes, that's why I've decided to avoid adding guppies or platies, though their commonly combined!  29 gallon doesn't feel big enough for when they reach full size. 
<Quite so. Mollies, if happy, will breed readily enough, so you'll soon find your tank filling up. To be fair, they're quite cannibalistic at times, but still, some will survive.>
 I do worry about population control though....  Not sure yet whom to add to eat the fry.  As they are not as assertive as the one's I returned, I worry a Knight Goby or Chromide might cause a clash.
<Knights are pretty peaceful, if predatory and territorial amongst themselves. The "Crazy Fish", Butis butis, is another wonderful low-end brackish predator. Gets to about 6 inches, looks gorgeous once mature, if a bit sinister.>
You say those need brackish too, and I am not wanting to go above 1 tbsp per 5 gallon regular aquarium salt due to the plants, so those probably wouldn't work.
<If you choose the right plants, they're fine in low-end brackish. I have no idea what specific gravity you have in your tank. Tablespoons don't mean much in oceanography! But let's assume that's three teaspoons, which at 6 grammes a piece is about 18 grammes salt total. 5 US gallons is 19 litres, so that's 18 grammes per 19 litres, less than 1 gramme/litre. That'll be having very little helpful effect, to be honest; it's less than you'd use for treating Whitespot on Neon Tetras or Clown Loaches, which is 2 grammes/litre. A low end brackish tank would be running at around 6 grammes/litre, and that'd be easily tolerated by salt-tolerant plant species, of which there are MANY. Do look at the plant list on my Brackish FAQ for more:
Virtually all hard water plants will be fine at this low-end salinity. If grammes/litre is confusing, you can use oz/US gallon (0.8 oz/gal) for the same 6 g/l salinity, or else a hydrometer, SG 1.003 at 25 C/77 F. My Brack Calc tool can be used for these conversions and t understand the relationship.>
I love having plants.  Though, I am attracted to Brackish fish and may someday start a separate tank for some.
<Hardy seems any point, if you have the Mollies already.>
At least these goofy balloon males are more mellow ...or should I say "lazy," and probably won't produce babies quite as frequently as the ordinary sort.  Though.....   Only time will tell.  I don't see what goes on at night or when I'm at work or in the other part of the house otherwise occupied.  I expect they will eventually score a family of fry.
I just hope as the males get bigger it will become more difficult and thus happen infrequently.  Balloon is like a deformity, and a recessive gene. 
Maybe Darwin will play out!  That's why I chose those for the males.
I will keep an eye out for aggression.  If necessary, there are a couple of pet stores who take a fish and give store credit.
I'm going to start a 10 gallon planted maybe for emergency situations, if I'm needing separation if I have to leave for work and can't return some fish beforehand.  I'm not sure what to put in it yet though ...maybe a single slow moving non aggressive fish. 
Can't just have an empty tank with no fish..... And a Molly might go after Endler's?  (which also breed profusely).  I guess I could do two FW Bumblebee Gobies perhaps.. Which I love. With lots of shells and caves and a heavy planting. I'd use the same amount of salt as for the Mollies.  They would probably be safe with the caves and shells and plant cover as I hope to be on top of things enough to spot aggression developing before it has a chance to become full blown.  Having a place to put a fish who was starting to act aggressive would be helpful.
<Good luck, Neale.>
Re: A Newby~ Question about fish compatibility for stocking a tank, and population control   1/8/12

Thank you, Neil. That plant list is awesome!
<Glad to help.>
I have Hornwort already, and some type of Anubias and I think some kind of crypticorn.  I don't know which one's they are but the store said they would tolerate low salt.....so they may be the same type and if not I can probably order some.
<Indeed. Cryptocoryne wendtii is by the most commonly traded Crypt, and the one that does best in the widest range of aquaria, including slightly brackish water. Surprisingly to some, there's even a Crypt that is a brackish water specialist, Cryptocoryne ciliata. This species isn't as widely traded, but is available, and given its large size, makes a fine centrepiece plant.>
I don't know about the poor anarchis, as I think I once read it doesn't. 
Though, I also read recently that it uses hard water minerals as fertilizer, which could explain why it is sprouting and growing roots like crazy!
<Quite so. Is definitely a hard water plant, and tolerant of low-end brackish.>
I'll sit down and figure out the salinity later, and probably I can just gradually increase it each time I do a water change.
<Exactly. No rush.>
I think I'll go with a knight goby once I hit the right salt level and the tank is fully cycled.  I love the little guys. You've sold me on that one, and that can finish off the 29 gallon, unless a couple Molly babies have beautiful coloring and suitable temperament and survive the larger fishes. 
But really, 6 Mollies and one goby gives everyone a little extra breathing space... So I may just trade any surviving babies for store credit to be safe and keep the little guys happy.
<Sounds good.>
<Good luck, Neale.>

Trying to stock a 35g hex BW    6/19/11
Hi there!
I just finished a fishless cycle for my 35g hex tank. I used ammonia as well as seed material from a mature tank to do the cycle and it took somewhere around 40 days to complete. I am using a Marineland canister filter.
I had originally planned on this to be a home for a rescued molly (I've had a lot of opinions given on what kind of molly he is. I can send a photo if you like, but he looks to be about full grown at around 2.5- 3", has a large sail-like fin, but I'm fairly certain he is not a Poecilia latipinna...maybe a hybrid), a few others of his kind and a few bumblebee gobies in a BW tank.
<Mmm, okay>
The molly was living in another tank with an equally rescued emerald catfish. I have since purchased more emerald catfish and 3 more mollies of the same kind, at least they appear to be!
<Brochis live under different water conditions...>
With that in mind, I prepared the tank with a very fine sand substrate, some stones and caves for the gobies and various silk plants at different heights.
I have come to realize that hex tanks are far from ideal, but this is what I have to work with. I have also started to shy a little away from the gobies. I think they are just adorable with their bulldog faces, but I worry about their feeding requirements and difficulty in finding them locally.
So, keeping in mind I was still planning on putting the mollies in this tank, what would you put with them in a hex tank environment?
<Many choices... I'd peruse the stocking areas on the brackish index of WWM: http://wetwebmedia.com/BrackishSubWebIndex/BrackishSubWebIndex.htm
esp. the Compatibility FAQs for Mollienesia>
Should I stand strong with the bumblebee gobies?
<Up to you. Are compatible system and behavior wise>
This tank is in a main room in the house so will be observed by many, so I'm hoping for happy, interesting fish. :)
Thanks so much,
<Welcome. Bob Fenner>

Mollies, gen. Incomp. w/ ADFs   1/28/11
Hi! I started a 14 gal freshwater tropical tank about 3 wks ago.
<Ah, this tank is a bit small for Mollies. Even if they live in the sense of water quality being adequate, maintaining the low levels of nitrate will be hard, and males will fight in such a small tank. For reliable results, treat 30 gallons as the minimum for Mollies.>
I started with two male balloon-bellied mollies, then added two ADF's over the next couple of weeks (since I didn't know that mollies prefer brackish conditions).
They seem to be doing fine.
<As they often do for weeks or months. The problem with Mollies is that they tend to become sickly over the long term kept in freshwater. Not always by any means, but easily 50% of the time. Hence the recommendation that Mollies be kept in their own tank, where water chemistry can be tweaked as required. They aren't good companions for frogs.>
I just have a few questions....(I don't trust PetSmart anymore) 1. I originally wanted to add more mollies to the tank, but reading info on mollies has made me think this would not be a good idea, as adding more male mollies would cause aggression problems, and I don't have the room to add enough female mollies for my two males, is this true?
<Is true. In 14 gallons you'd be lucky to keep one male and two females safely. Two females or three females even might be fine. But that's it.>
And if I do have room to add more fish, how many and what kind could I add comfortably?
<Do read up about what Mollies need, and then ask your question again once you've short-listed some species that get on with Mollies.>
2. The two mollies I have now are active and eat well, so I'm assuming their freshwater (with no aquarium salt) environment is ok,
<Don't bank on it. It's a crap shoot. Simple as that.>
since I have the two ADF's....is this true?
<Not true at all. Mollies and Frogs are poor choices for tankmates.>
3. I use a turkey baster to feed my ADF's at the bottom of the tank, and it still seems like they don't eat that much. How much should I expect to see them eating?
<Not a huge amount, but easily enough ever second day to slightly round out their bellies. Wet-frozen bloodworms are ideal "starter" foods. Once settled they eat a wide range of things, but variety is important, and dried foods should be used sparingly.>
4. Does water conditioner or AmmoLock ever cause pH readings to be off?
<Shouldn't do this, no.>
My pH fell from around 7 to between 5 and 6 after doing a 50% water change (the ammonia level in my tank had spiked) but my fish seem ok and that was like, 2 wks ago. Should I put some pH conditioner in there as well? I read that messing with pH while a tank is cycling can cause more harm than good.
Thank you very much for your time!-Michelle
<Do read about the needs of these:
Cheers, Neale.>
Re: Mollies  1/28/11
Thank you for your response!
<Glad to help.>
I'm sorry for asking so many questions; I'm new at this, and I'm getting so much conflicting information its difficult to sort through.
<Odd. The needs of Mollies, re: their preference for brackish water, is actually very well known and stated in every book I can think of. While some web sites might suggest otherwise, it's as well to remember the Internet is a hugely unreliable source of information. Always review carefully who says what and why. A retailer will tell you many things, but remember he/she is trying to sell you something too'¦ some retailers are wonderfully honest people, but others, a bit less so.>
So, I plan to separate my ADF's and my mollies; I purchased another small tank today for the ADF's.
<Do read up on the needs of these. Very small tanks, less than 5 gallons, aren't worth using.>
My question now is: What is the best way to go about transferring the frogs into the new tank?
<Divide the existing water out 50/50 between the new tank and the old tank. Move the frogs and Mollies into each tank. Top up both with dechlorinated water. In the case of the Mollies, I strongly recommend adding at least 2 grammes of marine aquarium salt mix per litre of water. Although splitting water does nothing to move bacteria between the two tanks, it will minimise shock through temperature and water chemistry changes.>
My original tank is still cycling, so the pH levels are a little low and the ammonia levels are unstable.
<Salt will help detoxify the nitrite, and this will help the Mollies immensely.>
Should I use some water from the original tank to transfer them into, or should I start over completely and begin cycling this new tank, then put the frogs in once its done cycling?
<You will need to divide the mature filter media between the two tanks. Around 50/50. Done that way, both tanks will be instantly mature. Top up both filters with new media, and that's that! Cheers, Neale.>
Re: Mollies, Aq. salts (FW) f'
Hi! Thanks for being so helpful...a little update and a couple more questions :)'¦.. I put the frogs in a 5 gal tank of their own. Now I'm trying to get the water right in the molly tank. I bought sea salt for it, but PetSmart told me to NOT use sea salt, to use aquarium salt instead.
<What do you mean by "sea salt"? Marine aquarium salt is precisely what you want. Sea salt used for cooking is not. As for generic "aquarium salt" as you'd use in a FRESHWATER aquarium to treat Whitespot is adequate but less useful. Your pet shop clerk is correct you don't want to use cooking sea salt, but absolutely wrong about using marine aquarium salt.>
So I put aquarium salt in my tank...it came in big chunks so I just put the correct amount of tablespoons in the tank, thinking the crystals would dissolve over time.
<No! Do not add salt this way! NEVER, EVER add salt directly to the aquarium.>
So, now how do I get the aquarium salt out to put sea salt in?
<You don't need to.>
Am I going to have to take out the gravel substrate and clean it or should I just wait a little while for the salt to dissolve completely then add sea salt to my water changes?
<Let's start again. Attend carefully! What you want is marine aquarium salt, for example Reef Crystals or Instant Ocean. PetSmart may even have their own generic brand. Ask the clerk for the salt used in marine reef tanks. That's the stuff! A small box shouldn't cost more than $5-10. Now, go home, and weigh out on kitchen scales precisely 5 grammes. That's how much you add to each litre of water IN A BUCKET. It should be a bit under one level teaspoon (which should hold about 6 grammes of marine salt mix). If your bucket holds 15 litres of water, then you add 15 x 5 = 75 grammes. Stir into the water until it's all dissolved. Add that to your aquarium with each water change. So if you take out 15 litres per water change, you add 15 litres of the water and salt mix. If you need to work in non-metric units, the concentration we're doing here is 0.65 ounces per US gallon. It's really very simple. Every time you take some water out, you replace that missing water with a new bucket of water to which JUST THE RIGHT amount of salt has been added FOR THAT BUCKET not the whole tank. Do that, and the water should stay very slightly brackish, about SG 1.002 if you have a hydrometer (well worth getting, a cheap glass one costs $5). If you need to, print this e-mail off, show it to the store clerk, and have them choose the salt mix and the hydrometer for you. Marine aquarium salt mix is BETTER than "aquarium" salt because it contains minerals that raise hardness and steady the pH, both essential to long-term success with Mollies. Hope this clarifies things. Cheers, Neale.>

Real plants and mollies   1/8/11
Hello Again:
<Hi there John>
I was wondering if it is silly to put real plants in with mollies as they are herbivores and probably would eat them, yet people seem to be able to do this??
<Yes... and a good idea too! Just need more plant material than they can consume...>
I was thinking of getting the real plants to offset algae.
<Mmm, not so much. There are many algae species that are unpalatable to Mollies, even some that are outright toxic>
I have five black mollies in a 20 gallon long, once a week water changes When I had Danios they tore the real plants apart
<Some do this>
I was down at the big box fish store today that listed "free snail" on the container with a live plant.
<Heeeee! Or was that supposed to read "Snail free?">
I think a snail would be a nightmare. The dude at another store wanted to sell me a $20 Swordplant then admitted the mollies would tear it apart
<I doubt that any but the largest of mollies, puniest of swords...>
My question is: Is there anyway to keep live plants with herbivore fish. It seems that people do this, but wouldn't the mollies go crazy on them, or do the plant leaves grow back? Is there a certain type of plant they ignore
<The plants can grow faster... they can even be separated by a clear panel (glass, acrylic) from the fishes... or species of plants used that they don't particularly care for (e.g. Ceratophyllum/Coontail) or are too tough (e.g. Anubias...) to destroy.>
Thank You!!!!!
<Welcome! Bob Fenner>
Really easy plants   1/8/11
<Hi there again John>
I was just writing about real plants for all female brackish Molly aquariums. I think it is better to get Amazon Frogbit, as they are low light thick plants and the fish can't tear them apart. I am wondering if I
am right??
<A good choice, yes>
Is Indian fern a low light plant also???
I guess I am looking for low light and lowest maintenance possible
Thank You!!
<You might do well to peruse our Planted Tank Subweb:
and here re Brackish Planted Sys.:
if you're employing much salt for your Mollies.
Bob Fenner>

Help if you can. Bottom feeder... attacks!    12/21/10
Hi there,
<Hello Tania,>
Don't worry the baby mollies are fine, I was just wondering if you could give me some advice on what to do about one of my fishes. I have a 3 bottom feeder,
<What's a bottom feeder? Do you mean Gyrinocheilus aymonieri, sometimes called the Chinese Algae Eater even though it doesn't come from China and eats very little algae? Or Pterygoplichthys pardalis, the Common Plec of the aquarium trade? Gyrinocheilus aymonieri is a highly aggressive and territorial fish that should not be kept in community tanks. Both Gyrinocheilus aymonieri and Pterygoplichthys pardalis need at least 250 litres/55 gallons.>
Corys, 3 Guppies, some tetras and now my 6 baby mollies along with their mother, I've noticed in recent days that one of my guppies tails seems to be getting strips taken out of it.
<Can happen. Do understand that male Guppies and male Mollies are aggressive once sexually mature. In the wild they attack one another to try to monopolise access to the schooling females. The strongest males drive away the weaker ones, so the only males that mate with the females are those males with the best genes. Much like the way lions fight to become leaders of a pride of females. Anyway, keep at least two (adult) females per (sexually mature) male, and keep either one male or three males, to avoid a situation where one male is able to bully one other male all the time. In other words, keep one male and 2+ females, or 3 males and 6+ females, but not 2 males and 4 females. Do further understand the minimum aquarium size needed for each species. Realistically, Guppies will need at least 70 litres/15 gallons, and Mollies at least 135 litres/30 gallons.
Anything smaller and it's unlikely the males will space themselves out enough to avoid fighting. Because Mollies are at least twice the size of Guppies, and therefore at least eight times as heavy, male Mollies can very easily damage Guppies when kept together. I would never recommend people keep them together except perhaps in a very large aquarium, 250 litres/55 gallons or more. The addition of floating plants provides hiding places at the surface, and so a few clumps of Floating Indian Fern is perhaps the single best thing you can add to a Guppy or Molly aquarium. Rocks and plants at *bottom* of the tank do virtually nothing useful since Guppies and Mollies are surface fish -- if you look at their mouths, you can see they open upwards, for slurping down insects at the air/water interface at the top of the water.>
I haven't seen any aggressive behaviour but could it be the mollies as they are getting older?
<Yes. Or the Chinese Algae Eater, if you have one. Nasty, nasty fish.>
I have now separated the guppy but don't really know what to do about it, They are only small strips but I don't want it to get to the point where I have to kill the fish.
<A breeding net (rather than a small floating trap) can be used to isolate the male until he heals, which he should do under his own steam. The use of an anti-Finrot medication would be useful, or else 4-5 grammes/litre salt, though salt at that concentration can't be used with Corydoras and other non-salt-tolerant water fish.>
Is there anything I can do?
<Do read about Guppies and Mollies.>
I am planning to give the mollies away when they get bigger but I was just wondering if you had anything that might help until then?
<Many articles here at WWM; start here:
Many Thanks
My smaller baby fish died yesterday as well, he seemed to just stop. Thank you for the advice on him though.
<Glad to help. Cheers, Neale.>

Question from Novice; Mollies & Corydoras? Hmm... no. 11/9/10
Hello, I bought my first tank about 2 1/2 weeks ago, and I'm already obsessed with the hobby!
<Cool. Glad to see you join the hobby. But please, direct some energy at reading, not shopping.>
I have two Dalmatian Mollies (1 male and 1 female) in a 3-gallon,
<Useless death trap.>
and immediately felt they didn't have enough room and got a 12-gallon.
<Much too small; need 30 gallons at least for Mollies.>
I also have 2 Panda Cat Corys.
<Essentially incompatible with Mollies. Mollies need hard, warm, preferably slightly brackish water; Corydoras need cooler water and don't like salt. Don't mix the two species. Just not worth it. The best catfish for Mollies are those that can tolerate slightly brackish water, e.g., Brown Hoplo Catfish.>
Now that we have the larger tank, do you think I should get another female Molly (to keep the male distracted a bit), and more Pandas?
<Neither; you need to sit down, think about what you're trying to achieve, and select fish accordingly.
The female Molly seems to be OK with the male, but I perceive as socializing could be harassment'¦
<Certainly true you need two females per male.>
And are Corys happier in greater numbers?
<Keep Corydoras in groups of five or more specimens per Corydoras species.>
Are 12 gallons enough for more Corys and/or another Molly?
<No. Not enough for Mollies, period. Just about adequate for five or six Corydoras, but hardly generous.>
Also, I was told not by the aquarium shop to worry about PH and testing the water, so I haven't done so, but upon researching online, I'm learning I should'¦?
<Damn straight. Your aquarium shop is wildly misleading you here. Sadly, that's not uncommon. Contact your local aquarium club -- most cities have one -- and you should get some worthwhile advice on good shops in your area.>
Any advice would be greatly appreciated! I am so new at this, and I really want my fish to be happy! Thank you, Andrea
<Do read:
Cheers, Neale.>
Re: Question from Novice 11/9/10

Thank you for such a prompt and helpful response!
<Always glad to help. Have fun! Neale.>

Re: Mollies 11/9/10
I wrote about a month ago, and I received excellent advice from Neale. I have a few follow-up questions.
<Fire away!>
I inherited nine Dalmatian Molly fry about a month ago. With suggestions from your site and Neale, I set up a 36 US gallon low-end brackish tank for them. The tank is now fully cycled, and it appears to be doing well (temp 80F, pH 7.8, ammonia 0, nitrite 0, nitrate 5ppm, dGH 290ppm, KH 180ppm, SG 1.004).
<If you have problems with plants, cut the salinity by about a half; SG 1.002 should be fine for Mollies, keeping the benefits of slightly brackish conditions but with minimal stress on plants such as Indian Fern, an ideal species for livebearers tanks in many ways.>
Now that the Mollies are about four months old, I can see that I have five males and four females. So far, the males aren't chasing the females (perhaps they haven't yet become sexually mature?),
<Oh, they're mature, but their hormones really won't kick in until they're nearly fully grown. Dominant male Mollies can be very aggressive. Does vary though.>
but I know it is only a matter of time before that begins. I understand that the current ratio is nowhere near ideal, and my question is how to best rectify that. Should I add females?
If so, how many Mollies can I safely (and happily for them) have in a tank my size?
<Oh, in a tank this size, allow 3 gallons per Molly, assuming these are "shortfin" Mollies rather than the bigger "Sailfin" Mollies.>
Also, I would like to have as few fry as possible (a space issue more than anything). Neale suggested keeping Knight Gobies and Glassfish to keep the fry count low. I am more partial to Glassfish, and if I wouldn't be overcrowding my tank, I would like to purchase some to deal with the fry.
None of my local pet stores stock Glassfish, so I would be forced to purchase them online; is this an awful idea? I can find three different species available: Giant Glassfish (Parambassis qulliveri),
<Parambassis gulliveri, a big (to about 22 cm/9 inches), predatory, and rather feisty species; excellent and very beautiful freshwater fish, but not for this tank!>
Indian Glassfish (Parambassis ranga),
<Yes, this is a good species for either fresh or brackish water. Less predatory than Knight Gobies, but should make a dent on fry populations.>
and Longfin Glassfish (Gymnochanda filamentosa).
<Very delicate soft water species; not recommended.>
Which, if any, of these would be best, and roughly how many should I stock?
<You want to keep Glassfish in reasonably large groups because they are quite grumpy fish that chase one another. I'd get at least three, and ideally five or more. Allow two gallons per fish.>
Finally, it might be that one of my female Mollies is just now big enough for it to become pronounced, but over the last week or so, she has become slightly deformed. Starting roughly at her dorsal fin going toward her mouth, her body curves left. She is just as active as the other fish, and she eats well, but she does swim slightly crookedly. Is there anything I can do?
<Not really. Dietary issues are sometimes to blame, so review diet. But once the deformity is there, it won't go away. Inbreeding in fancy livebearers means that poor genes, and resulting deformities, are extremely common.>
Thank you so much!
<Glad to help, and enjoy your fish! Cheers, Neale.>

molly tankmates? 8/29/10
We have a fully cycled 120 gallon brackish water (1.009 SG) tank, planted with java fern and java moss.
<Are you sure you're at SG 1.009? I don't believe you are; that's about 40% seawater salinity and will kill both Java Ferns and Java Moss. Go check again, and perhaps calibrate your hydrometer to make sure it's working. 15 grammes of marine salt mix in 1 litre of water will be SG 1.009 at 25 C; that's about 1.9 oz per US gallon. For Mollies you don't need anything like this much salt. SG 1.002 at 25 C is ample. That's 5 grammes of marine salt mix per litre, or 0.65 oz per US gallon.>
Ammonia is 0, nitrite is 0, nitrate is 10ppm, 30% water change weekly. The only inhabitants at the moment are mollies. Most of them are sailfins, with a few balloon mollies that we moved from our freshwater tank as well. We move the babies to a separate tank so that we can take them to the LFS when they are big enough. I am wondering if there are any suitable
<At 1.009, anything from the brackish water selection should do fine, assuming the right social behaviour. Options might include Scats, Monos, Archerfish, Orange Chromides, Butterfly-Goby Waspfish, Knight Gobies, Crazy Fish Sleeper Gobies, Violet/Dragon Gobies, among others. At SG 1.002 you could keep some of these, for example Knight Gobies, as well as salt-tolerant freshwater fish such as Rainbowfish, Guppies, Swordtails, Platies, Brown Hoplo Catfish, Glassfish and Bumblebee Gobies, among others.>
My children are very attached to them, so I am not interested in adding anything that will eat anything larger than fry.
<Well, Archerfish will eat the fry and in fact anything they can swallow.
Monos will certainly eat fry, as will Waspfish, Knight Gobies and Crazy Fish. But Violet Gobies are non-predatory despite their size, and Scats are more or less herbivorous, and tend to ignore fry if they have something else to eat.>
The reason the SG is as high as it is, is that I would like the option of going to a full marine tank at some point, and wanted it to cycle the first time with marine bacteria in the bio filter.
<I see. Well, I can't imagine the plants will last for long.>
Anything that I add would have to be able to tolerate full salt water as well as the current brackish conditions. Am I destined to a species only tank at the moment?
<Far from it. In a mid-salinity brackish water system you can actually keep a very wide range of livestock. At a slightly higher salinity you may even keep some marine fish and invertebrates as well. If you haven't seen my Brackish FAQ, do read here:
On the other hand, if your interest is really to nudge towards marine conditions, there's much to be said for losing the plants, upping the salinity to at least SG 1.018, and installing live rock for decoration. You can then gradually add hardy marine fish such as damselfish and gobies as the months pass, until such time as you feel ready to upgrade the lights
and add corals and polyps. Alternatively, you could stick with the live rock and just add some hardy shrimps and starfish, and thereby create a FOWLR system.>
All suggestions are much appreciated. Thank you very much in advance.
<Cheers, Neale.>

Fighting Mollies, Neale's go  8/9/10
Dear WWM Crew Member,
First of all I would again thank you all for the excellent support and help in the past. I am recently having a problem with two golden molly.
I have attached a picture...in which A and B (as I marked them in photo) are seen. I bought them just 3 days back.
<Do start by reading here:
Mollies are not "easy" fish.>
Now all the day they are fine and playing. How ever at feeding time A chases B whenever it (i.e. B) tries to eat.
<Male Mollies are extremely aggressive. Continual stress will lead to death. Make sure the aquarium is very large if you have two males. For Sailfin Mollies, I'd say 30 gallons for 1 males and 2-3 females; at least 55 gallons for 2 males and 5-6 females.>
[ I feed them dried worms] .
<Will need other food. These fish are VEGETARIAN. Worms are fine as an occasional treat.>
as a result B gets less food. I also tried to divide food in two parts, but still A eats its part and also chases of B while it tries to eat.
<Yes, what they will do.>
however A does not try to eat B's food...it just chases it. Can U tell me possible reason for it..and what should I do?
<Read, and act accordingly. What your specimens are doing is ENTIRELY NORMAL for the species.>
Thank You again in advance
<Hope this helps. Cheers, Neale.>

Fighting Mollies, BobF's go  8/9/10
Dear WWM Crew Member,
First of all I would again thank you all for the excellent support and help in the past.
I am recently having a problem with two golden molly. I have attached a picture...in which A and B (as I marked them in photo) are seen.
<Are these two males? One definitely is... I suspect the other as well>
I bought them just 3 days back..Now all the day they are fine and playing..How ever at feeding time A chases B whenever it (i.e. B) tries to eat.[ I feed them dried worms]
<...? Need more, different than this>
..as a result B gets less food. I also tried to divide food in two parts, but still A eats its part and also chases of B while it tries to eat. however A does not try to eat B's food...it just chases it.
Can U tell me possible reason for it..and what should I do?
<Read...: http://wetwebmedia.com/FWSubWebIndex/mollies.htm
and the linked files above. There is a much preferred sex ratio with most Poeciliids, all Mollienesia... you need to search, study what is archived on WWM, ahead of writing us... But do write back if anything is unclear,
incomplete to your understanding. Bob Fenner>
Thank You again in advance

Sickness... Tetras and Mollies mixed together...    6/29/10
I have 6 fish in a 10 gallon tank. Four are Red Minor Tetras and two are Balloon Belly Mollies, one male and one female.
<Mmm, these fishes/species can't be mixed successfully. The Tetras like softer, acidic water of higher temperature, the mollies enjoy harder, decidedly more alkaline water that is cooler...>
I got them and two of the tetras on Monday.
<... is this system cycled?>
All four have been eating excessively while my other two tetras are hardly at all. The male molly has been eating the most out of them all. When I first put the mollies in the water they kept going to the top and blowing bubbles. They aren't so much now, especially the female.
She keeps sitting at the bottom of the tank and only moves when the male darts up and chases her. I have a little cave thing that she keeps going in and sometimes she squeezes herself into the corner behind it. Yesterday I found her in the cave with my Black Snail so I picked up the cave in case she was stuck. Is there something wrong with her? Is she possibly pregnant?
<Read here: http://wetwebmedia.com/FWSubWebIndex/charsysfaqs.htm
and here: http://wetwebmedia.com/FWSubWebIndex/mollies.htm
and the linked files above. What you have here won't work. Bob Fenner>
Re: Sickness... not following reading...
It won't work? The lady at PetSmart didn't say anything and both species are listed as community fish. Do you have any suggestions in case I can't get a separate aquarium?
<... return one or the other species, read where you were referred to... fix the environment to suit the remaining>
By the way, I've heard about a disease thing that causes white gunk on fish. My tetra have white on their bottom fin things, but I can't tell if it's part of their color or not.

My new fish :D Molly, Angelfish, Newt incomp.    1/31/2010
Hi There!
My name is Libby.
<Hello Libby,>
I have owned and operated my own fish tanks for about 12yrs now. I just got a couple of freshwater angelfish today and I also picked up a couple of Marble Lyretail(sp?) Mollies.
<Not an ideal combination. Although Mollies sometimes do okay in plain freshwater, they are more reliably in slightly brackish water. Angels, on the other hand, are soft water fish, and while they'll live in hard water, they won't tolerate brackish water. In other words, these are two types of fish you'd be unwise to mix. Do read here:
I'm in the process of floating them in their tank (which are two separate tanks I'm working with). One tank I have is about 10g and is currently housing a Paddle Tail newt (Sally) whom I have had for about 6yrs.
<Well, these are coldwater amphibians, and have no business living with tropical fish.>
My other tank which is about 5g is currently empty, and is temporary housing for my Angelfish until I set up my 30g tank. I was originally planning on introducing my Mollies in with Sally.
<Nope. Optimal water temperature for your newt, Pachytriton labiatus, is 15 degrees C; Mollies and Angels are both hothouse flowers that need temperatures above even those of the average tropical fish, and are best kept at 28 degree C or even slightly higher. There's no overlap here at all.>
Sally has lived with many other fish in the past and only gets aggressive if she gets bothered first. Other than eating old, dying fish, I have never been concerned with her attacking and killing my other little buddies. She's even been homed with Tetra's before and never harmed them.
<You really are keeping your newt far too warm. Do please review the needs of this species. Your newt will have a much shorter life kept too warm.>
I've had Sally with Mollies before, but I'm wondering if I would honestly just be better off with introducing my Mollies to my Angelfish. My only concern is if they would get along okay. I've never owned Angelfish before, but am very prepared for the road ahead of me.
<Farmed Angels, which is what I assume you have, are quite straightforward fish. Do read here:
I would really like to have them together, but I'm wondering if the Mollies would be too aggressive with my Angels?
<They're a bad combination because of differing water chemistry requirements. In terms of behaviour, they should ignore one another, but both species have the potential to be aggressive, occasionally cause major problems in community tanks.>
Is this something I can accomplish? Should I just play it safe and keep my Mollies in Sally's tank? Gosh, I have so many other questions I don't know where to begin, but I guess this will do for now :). I hope to hear from you soon!
<Time to do some reading, I fear. Hope this helps, Neale.>

Aggressive or mating mollies? -- 11/23/09
Hello, I recently added a male and female Dalmatian mollies to my 10g tank.
The e tank already housed 1 dwarf Gourami, 2 male fancy guppies and an African dwarf frog. The male molly seems to pick on the female every once in a while. Sometimes they'll be swimming together just fine and dandy and then a couple min. later it looks like he starts to nibble at her side.
Are they mating or is he picking on her? I have searched and searched for the answer and have found NOTHING! Please help!
Thanks! Kendra
<Hello Kendra, you couldn't have searched very far! Honestly, Mollies can't be kept in a 10 gallon tank precisely because the males are so aggressive.
You also need to keep at least two females per male, otherwise the male will pester her. This is so stressful for the female that miscarriages become a very serious possibility. Do read here:
A 20 gallon tank with hard water and preferably a little marine salt mix added (3 grammes per litre should be fine) is what you want. Stock with some floating plants such as Indian Fern to give the female some cover; baby fish will also hide in the plants long enough for you to find them and remove them to a floating breeding trap. Guppies tolerate salty water well, but Frogs will not, aren't compatible with Mollies. None of these is news, and if you'd looked in any aquarium book, you would have come across information along these lines. Cheers, Neale.>

New owner of Dalmatian mollies, comp., no data    3/23/09
<Hello Saara>
I am in desperate need of an answer as to why my female Dalmatian molly is constantly poking at the male molly? He just lays there at the bottom of the tank and the female comes around every few seconds
and attacks it. Is this normal or am I going to lose a fish????
<It may be that this system is too small... mollies are social animals that live in aggregations, spaces that allow them to interact and get away from each other in mixed sexes settings... How big is this system, of what water make up... Please read here:
and the linked files above should you have further questions categorically.
Bob Fenner>

Aggressive female molly 8/07/08 Hi, we have had this molly for about 3 weeks now (I think she may be pregnant) and she has suddenly became aggressive. I noticed this morning that she is pecking at the other mollies and has practically killed one of the other females. I just did a 50% water change today. Our pH level was a little high when we had it checked yesterday (that's why we did the water change today). Is there something else I am missing? Could it be over feeding? <Hello, Merritt here today. First, I have a question for you, how big is your tank? Mollies can become very aggressive towards one another if the aquarium is not large enough. This means you may need to shop around for a larger home for your mollies. Also, mollies are very sensitive to water parameters, so get that pH in check. You could also increase the size of the group with an addition of more females, if your tank is big enough. Here is a helpful link that will aid in your molly care. (http://www.wetwebmedia.com/FWSubWebindex/poeciliids.htm)> Alicia Borton <Good luck, Merritt A.>

Re: My female molly has became aggressive   8/8/08 Reply to aggressive Molly My tank is 10g, <Too small for these active, aggressive fish...> and I have had 3 of them die since I last emailed you. <What's the water quality like? What's the water chemistry. Unless you're keeping them in clean, warm brackish water -- that's your problem, end of story. Aim for 26-28C, pH 7.5-8, hardness 20 degrees dH, and a salinity between 6-9 grammes marine salt mix per litre (about SG 1.003-1.005).> I noticed on one that it had this white mucusy substance hanging from its fins and coating its sides. <Standard reaction to Mollies being kept in poor/wrong water conditions. Is this a brackish water tank or not? If not, these fish aren't going to magically get better and stay better, even if you treat with an appropriate medication such as Maracyn or eSHa 2000.> I looked this up on the net and it said it is a bacterial infection. <Covers a lot of ground! Gangrene and TB are both bacterial infections!!! So, we need to be a bit more specific here. What you've go going on is something like Finrot and/or Fungus. Mollies are EXTREMELY prone to this when kept too cold, in too acidic conditions, in poor water quality, and in freshwater conditions (rather than brackish or marine).> My finance went and bought "Quick Cure" and this will be the third and final day of treatment. <Not familiar with this medication. Wouldn't recommend it on that basis, but if it treats what I'm talking about, OK. Do of course use as instructed, above all remembering to remove carbon from the filter. None of these medications will work unless underlying conditions are improved.> The remaining two that are left are doing better but not back to normal, my male is hanging around the bottom a lot and only coming up for food (he still can't make it all the way to the top). <Very sick.> The website said something about swimmers bladder, and that they would be dead in 12 hours or less, but we have made it 48 hours since we started treatment. <What web site is this? All sounds pretty dubious to be honest.> Any other suggestions? <Yep, lots. Please start here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm > "Kites fly, and so should you" <Should I? Not wild about sitting in thin steel tubes hurtling through the sky at huge velocities.> Alicia <Cheers, Neale.>

Re: My female molly has became aggressive   8/8/08 I am not sure of the websites now. <OK.> It looks like our local pet store has informed us wrong on buying mollies... <Not uncommon.> We were told that they can live in freshwater condition, no salt. <And 50% of the time Mollies do fine in hard, alkaline, clean, warm freshwater. But if you want 100% success, keep them in brackish. A brackish water system for Mollies isn't difficult: add 6-9 grammes of MARINE AQUARIUM salt mix (e.g., Instant Ocean) to each litre (0.8-1.2 oz per US gal) of water before you add it to the aquarium. Stir well so the salt dissolves. Top up any evaporation with water from the tap, not with salty water. That's it! Not difficult.> We have basically bought the fish tank for our 2 year old that loves them, is there any suggestions you can give us on what type of fish that are low maintenance and pretty easy to take care of? <In a nutshell, you shouldn't be buying fish (or any pet) FOR a two-year old. Buy pets for yourself, and introduce your offspring to the pleasures AND responsibilities that come with caring for an animal. But if you want something low maintenance, get a Furby or something. As/when the child gets bored you can give the thing away, no harm done. Even an easy fish species -- like Platies -- will want 25-50% water changed per week, a tank at least 20 gallons in size, a properly maintained filter, a varied diet, the right water chemistry and the right temperature. I'd consider Platies low maintenance, but if that sounds like too much work for you -- then fishkeeping isn't sensible. And before you ask, Goldfish are EVEN more hard work; the vast majority of Goldfish are kept in grim conditions and die pretty quickly. Bowls are death traps, so don't even think about them. What fishkeeping isn't about is teaching children that animals have no worth and can be replaced whenever they die. Instead teach children that animals are wonderful companions, but if you want to keep animals, there's some work that comes with it.> I really like the Mollie but it seems that we are in over our heads, and that is not what we are wanting. <I've written something about selecting species, here: http://www.wetwebmedia.com/FWSubWebIndex/fwlivestk.htm Have a read, and once you've got some ideas about the size of the tank, your local water chemistry, and so on we can discuss some of the options in depth.> Thanks for all your help, I really appreciate it. Alicia <We're more than happy to help. Cheers, Neale.>

Can I mix mollies with tilapia   7/23/08 Sent from my CrackBerry® wireless device available from BTC. <Not really, no. Sent by Neale from a shiny silver computer available from Apple.>

Molly attacking Goldfish 4/7/08 Hi WWM! <Hello> I have a 10 gallon tank with one butterfly goldfish, one creamsicle Molly and 2 Mickey Mouse Mollies. <Too much and incompatible life in this tank.> I didn't know until now that mollies are not supposed to be in the same tank as goldfish because I've never owned fish before. <Read before you purchase livestock next time.> They seemed to be getting along for a couple of months, however, for the past month or so, the creamsicle Molly has been attacking the goldfish by constantly "biting" or "nipping" its back fins causing them to become frayed. <Common behavior for a molly.> The goldfish seems very upset and unhappy and tries to hide from the Molly but can't escape it. Can the goldfish die from this? <Can contribute to its demise.> What should I do? <Separate the fish, provide a more appropriate habitat for them.> Thanks, Antoinette <Welcome> <Chris>

Sick Molly... env., mis-mixed with goldfish  12/07/2007 First I would like to thank all of you. Any time I have a question some one always answers me. So thanks. Now onward. I have a 10 gallon tank. I have 3 mollies and 4 goldfish. Now I know they like different water situations and found this out after the fish were bought and put together (need to do my homework, I know). However, every fish was doing fine but now ALL my mollies have what appears to be fluffy white spots on them. Not sure if it's a bacteria or a growth...what can I do? Also is the water contaminated now to, so if something does end up happening to my molly's will it contaminate the next fish? Thanks so much. Laura <Hello Laura. The Mollies have Finrot and/or fungus and need to be treated with a combination Finrot/fungus medication. This is extremely common when Mollies are kept in freshwater. In addition, Mollies are acutely sensitive to Nitrate, and Goldfish are veritable Nitrate factories! So you WILL need to separate them. Please do read our article on Mollies and act accordingly: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm Hope this helps, Neale.>

Question about Mollies & Tetras  9/7/07 Hello, <Ave,> I have a 30 gal. tank with only 6 fish in it. There is a Blackskirt tetra, a silver sail fin molly, a plecostomus and two platies. <Not a good selection. The Blackskirt tetra (by which I assume you mean Gymnocorymbus ternetzi) is [a] a schooling fish and [b] a notorious fin-nipper given that wild fish feed partially on the scales and fins of slow-moving fish. Plecs (in your case, likely Pterygoplichthys sp. rather than Hypostomus sp.) are massive fish that easily reach 45 cm in captivity and consequently need an aquarium around twice the size of yours to be kept safely. Finally, mollies are just plain easier to keep in brackish water, which your other fish don't want.> All of them are male, I think, but I had two females (one a platy and one a molly) that I had to give to a friend because they were constantly breeding. <Absolutely no way you can sex the tetra or the catfish.> Recently, the silver molly started chasing the tetra around the tank, getting in front of him and displaying his upper fin in his face, kind of like a screen. <Mollies are aggressive, and in the wild, adult males dominate patches of water, driving off other, weaker males and monopolising access to the females in the area. In short, yours is doing what comes natural. It is entirely normal for them to chase other species. I've seen this myself between mollies and rainbowfish, for example.> It's gotten so bad that the tetra doesn't seem to want to eat. So, I went to PetSmart and asked what to do. They told me to add another Blackskirt tetra because the molly is displaying his 'dominance' as the tank king. <Garbage advice. As a rule of thumb, anything quoted by a big-chain pet store is more likely to be wrong than right. They tend to employ casual rather than expert staff, don't train them beyond selling and customer service, and have no investment in anything other than you coming back to buy more fish. There are exceptions I'm sure, but on the average if the person you talked to looks like a student working a Saturday job, best avoid.> So, I added a new tetra, and now the molly is going crazy chasing both!!!! <Quelle surprise.> What should I do? <Up to you. If it was me, I'd decide on what sort of aquarium I wanted. Do you want a school (i.e., 6) Blackskirt tetras? Do you want a school (i.e., 6) platies. Do you want to keep mollies? The catfish has to go, I'm afraid, keeping it would be wrong. Me, I like mollies, and I'd go buy 2-3 more females to go with the male. I'd then convert the tank to a brackish system by adding a small amount of marine aquarium salt mix (not aquarium or tonic salt) with each water change (3-5 grammes per litre will do). I'd then add some gobies or flounders to the bottom of the tank. The mollies will ignore these completely, and they'd make for a fun, quirky aquarium. You could keep the platies in this tank, too, as they do fine in slightly brackish water. The tetras, though, would have to be removed.> I really do not want to add any females because I do not have that much room for the fry. And the last time they were breeding, I had to isolate all the fry (because I didn't want them to be eaten!) and it was just a huge mess! <Just let them get eaten then. If you kept a couple of knight gobies (Stigmatogobius spp.) believe me, they'd get eaten! Otherwise, remember that you can always sell on young fish. That's what I do. If you have lots of real/plastic plants in the aquarium, at least some baby fish will survive. Having a separate tank to rear them in works well, and means that you cut down costs on things like food by trading in baby fish each time you visit the pet store.> Any advice would really be appreciated! Thank you, Crystal <Cheers, Neale>

Re: Question about Mollies & Tetras  9/7/07 Hello Neale, <Hello Crystal,> Thank you so much for your reply! I really appreciate it. The two tetras are sticking together and it seems that molly is leaving them alone, he displays his fin once in a while, but it seems the two tetras are ignoring it more and the older guy ate last night! :) <Very good.> I plan on getting a larger tank, I have been saving up for one, so I could keep the baby Plec ( a friend told me they grow fast) the one I'm looking at is a 50 to 60 gal, do you think that might work? <Sounds great.> I plan to keep the smaller tank in another part of the house, do you think I can convert it for a brackish system? I was wondering what other fish normally get along with mollies (+they would have to live in the brackish system) and is it okay to keep them all male too? <Converting to a low-end brackish tank would be easy. Lots of fish would work well here with the mollies -- bumblebee gobies, glassfish, wrestling halfbeaks, knight gobies, crazy fish, orange Chromides, flatfish... Have a read around the Brackish section here at WWM and see what's small and tickles your fancy. A brackish tank isn't any more difficult to run than a freshwater one, and in some ways easier because the marine salt mix tends to make disease less of an issue and buffers against water chemistry changes. You only need to add 3-5 grammes of salt mix per litre of water, so it isn't expensive, either.> And what other fish get along with the tetras, since I plan to get more of a variety of color for the larger tank. <Blackskirt tetras are best mixed with tetras, barbs, and rainbowfish in the middle of the tank as well as active bottom dwellers like catfish and loaches. The things to avoid is anything slow or with long, trailing fins. Bettas, angels, fancy guppies, gouramis, etc would all be bad choices. So it's really not difficult to mix them with other fish, you just need to be a little more picky than normal.> Your advice is much appreciated, the only pet store near me is a PetSmart and I do agree-it seems like I'm constantly buying something there and they never really answer my questions! <I'm sure they mean well, but a store is a store, and largely interested in making a sale. My grandfather used to say about doctors that they had no vested interest in making you healthy, since healthy people don't need doctors. They just didn't want you to die because then they lost a customer! A lot of pet stores are run the same way... so long as you keep coming back to buy replacement fish and new bottles of medication, they're happy.> Thank you, Crystal <Good luck, Neale>

Compatibility with Mollies  -- 08/08/07 Hello, We have an 80 gallon tank with 4 tiger barbs, 6 Mickey platy's, 3 dwarf gourami's and 4 Dalmatian molly's. Are all these fish truly compatible with types of water and conditions? Since we have 80 gal we would like to add more fish, what would you suggest adding to the tank more of what we already have or additional breeds)? Heather Joubran >>>Greetings Heather, Jim here. Those fish are fine, and there are too many other options to name! Look at the various tetra species for starters, as well as the dwarf cichlids of the genus Apistogramma. There are also the Cory catfish, other types of gouramis, on and on. Feel free to write back with any specific questions! Cheers Jim<<<

Re: Compatibility with Mollies 2  8/9/07 Hi Jim, I do have a medical question and it's probably hard for you to answer because I do not know any of the water settings. We have had a tank for about a month. We got everything setup and let it sit for a week, then introduced 5 fish the mollies and gourami's. The following week introduced the rest. One Dalmatian molly I believe is ill. We have 4 in total from what I can tell 2 males, 1 female and the one that is ill I believe to be a female. Here's the issue. A few days ago this molly started sitting at the bottom of the tank and was in a some what bent position. Tail fin scrunched together. I thought it was dead but went to scoop it and is swam off. It has been hanging out on the ground. It appears to shimmy or what I would call it attempt to swim but isn't getting anywhere. From time to time it will attempt to swim towards the top of the tank. Not sure what to do with the fish, yesterday we had a blue dwarf Gourami hang out at the bottom. Last night I noticed it looked like it's dorsal fin was bit and maybe a bit on it's side. This morning it was dead. I removed it from the tank and didn't notice anything else wrong with it. Last night we also do a 30% water change first since we have had the tank. Everyone else is doing great and really happy in the tank. What are your suggestions and what do we do with the one molly? Heather Joubran >>>Heather, look again and see if you see any more evidence, patches, spots, etc. Then use these links...http://www.waterlife.co.uk/waterlife/disease.htm http://www.klsnet.com/files/fishchart.htm This is easier then me trying to figure it out based in the information given. It could be one of a few things, but those links are easy to use and should help you narrow it down. Feel free to write back! Cheers Jim<<<

Molly aggression   4/23/07 Hi, <<Hi, Diane. Tom here.>> I have a question about my Mollies. <<Okay.>> I have a black lyre tail (M), a grey/black (?) and a white/black (F) Dalmatian lyre tails, and a 'creamsicle' (?) lyre tail molly (4 total) in a 10 gallon tank with 2 snails, a Cory catfish and an African dwarf frog. <<A lot going on in a ten-gallon tank, Diane. Too much, in fact. You need larger quarters for these fish.>> The Grey/black molly is being bullied by the other 3 mollies to the point of swimming around tail down in a submissive type posture the past few days. When the others come anywhere nearby, it quickly retreats, especially when feeding, or the others will nip at it. I have seen them in a 'head over tailfin tussle' on a few occasions mostly with the black one.   <<A couple of thoughts here, Diane. If the 'question mark' fish are females, they might be sorting out a 'pecking order', which could explain some of the bullying on the parts of the other females. The male would be a 'case' unto himself. My other thought is that fish seem to have a 'sense' about other fish. For reasons not readily apparent to us, they'll single out another of the group that doesn't fit in. The fish might be sick, weak, too submissive. In short, unable to fit into the scheme that they've laid out. Hate to be redundant, but these fish are in small quarters. Do you need to spend mega-bucks for a huge tank? Nope. We're hobbyists just like you. (And, none of us has won the Lottery that I know of. I sure haven't!) You can upgrade, given the space, without 'spending an arm and a leg'. Doubling the size to 20 gallons (tripling it to 30 would be better) would take care of a 'world' of potential issues, including, I believe, the one you have.>> The snails, frog and catfish are unbothered. <<They won't be. This is a fish-on-fish issue, Diane.>> I feel sorry for this fish and I'm not sure what to do, any suggestions? <<Aside from what I've already given you, isolate her with a tank divider, if possible. This will exacerbate the 'space' problem but keep her out of harm's way. With one 'goofy' fish,  there are steps we can take outside of this but, three-on-one calls for more dramatic steps.>>   Thanks, Diane <<If you would, Diane, I'd like your feedback'¦no matter how things go. There are some 'givens' in the hobby and, other times, we have to fly by the seat of our pants. Best of luck. Tom>>

Re: Molly aggression (follow-up)   4/23/07 Thanks Tom, I appreciate your feedback so quickly.   <<No problem, Diane.>> This 10 gallon tank is a relatively new upgrade from a 3 gallon tank. Real estate in my home is a prime so I hesitate to go any bigger if I can help it. I do however still have my 3-gallon tank that my frog had been happy in for the past year and a half. Would it be helpful to move the frog and possibly the grey molly back into the smaller tank to help create more elbow room? <<As a 'stop gap' measure, I think this would be appropriate, Diane. I don't think this is a long-term solution but, working with what we have, I think it the best way to go right now. Thanks for getting back. Tom>>

Mollies & Dwarf frogs compatible?   3/8/07 The African Dwarf frogs are cute. Before I consider a purchase, just a quick question - I have about 20 mollies and noticed they enjoy chasing & playing with each other. I am concerned wondering if mollies (and a few bottom feeders as Corydoras in the tank) will be nice to the frogs, e.g.. will not nip their little webbed feet when floating on the top? I want to make sure I never mix any incompatible species and wondering what your opinions are. Thank you so very much for your time! SK <Generally these three groups/species do get along fine... though I would like to state that neither Corydoras genus catfishes nor ADFs "like" salt/s in their water... and many folks use such with Mollienesia species. Bob Fenner>

Re: Mollies & Dwarf frogs compatible?  -- 03/09/07 I may try a couple of the dwarf frogs. In my tank I have never added salts. <Good> All but two of the Mollienesia fish I have were born in that very tank. <Ahh, the best means of acquisition> No salts added, though the dip stick reads as me having very hard water - I use the aqua safe dechlorinating products.  Does hard water, aqua salts, and a brackish environment correlate in any way? <Yes... the harder the water, the more total dissolved solids... many of which are salts (ionic combinations of metals and non-metals...)... so much concentration of these solids in a given volume of water is what brackish is. Bob Fenner>

Molly Mobsters? Overcrowded, mixed with Goldfish...   8/11/06 Hi, <Hello there> I started off with 20 fish in a 45 litre tank, <Likely too many for this volume...> adding them gradually in case of sickness. Things were going fine until they started dying one by one for what seems to be no apparent reason. There are no visible signs of sickness and the only sign that something is wrong is that one at a time, they start to hide out and not eat. It seems to be one fish a week. I am now down to 6 mollies (4 black & 2 white), Balkie Plectocomous (my Plecostomus) and the two new additions, (Marilyn and Monroe) my goldfish. <... goldfish are not tropical... should not be mixed with...> I have noticed that the mollies chase the other fish around the tank in what I originally thought was "playing". As the fish have been dying off, I have noticed that the fish dying are usually the one's being chased around. The mollies seem to be relentless in their "pecking" of the other fish. Every time I see the mollies doing this, my blood starts to boil, most especially since the last to be bullied were my flame dwarf gourami's who took turns in being the victim and eventually passed on. Now it seems that Marilyn the goldfish is being bullied to such an extent that her swimming is wild when any of the mollies come near her which seems almost constant. Monroe seems unaffected as yet but I have my suspicions that his days will be numbered as soon as Marilyn dies of a fishy heart attack. Is this normal molly behaviour and is it possible that the mollies are actually causing all these deaths in my tank? I am about ready to flush the little ******* down the toilet and start over. I have had mollies before but never seen this type of behaviour in them. Little Fish <Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwsetupindex.htm re the species you keep, intend to keep, their Systems, Compatibility... Bob Fenner>

Oh Golly Mollies, Salt, pH, etc. - 10/21/2005 Hello I am new to salty systems. I've always had freshwater aquariums which I still run two. But I saw some Dalmatian Mollies and had to get some. I have one male and three females. I do plan on adding maybe two or three more mollies and an algae eater and that's all this tank will have in it. I don't want to overcrowd them. I talked to three different fish stores to set up my system to get it ready. (I wish I had found this site first.) So I set up a 29 gallon tank with one teaspoon of salt per 5 gallons of water. Should more salt be added? <Nah. Especially not if you plan on an animal for consuming algae. With salt in the water, I would recommend using Caridina japonica, the "algae-eating" shrimp, as these fare well in slightly salty conditions.> I have an Aqua Tech 20-40 power filter at a flow rate of 160 Gph with bio fiber. Is this ok or would a bio wheel be better? <Mm, whatever you prefer. If you've already got the Aqua Tech, I see no reason to buy something different.> All the stores said a pH of 7.2 was right; mine's between 7.4 and 7.8. <This is fine - BUT - please don't let it be *fluctuating* between these.... far too much fluctuation between 7.4 and 7.8 to be safe. A steady pH is pretty important.> The temp is at 80 degrees. I see on you're site you recommend a high pH so should I get some crushed coral sand to raise it, or is it okay at the level I have? <Constant, steady pH is better than precise pH. You'll be fine with what you've got, I think.> Also I do test the water with strips but this just shows a range of where it should be. So should I get a better testing kit if so what do you recommend? <I would. Look for a quality liquid-reagent test kit.... Kordon makes 'em, so does Aquarium Pharmaceuticals.... You'll need pH, ammonia, nitrite, and nitrate most essentially.> Thank you for your time. -David <Wishing you well, -Sabrina>

Not The Greatest Mix, and Maybe Velvet - 10/18/2005 Hi and thanks for a great site! <Good morning, and thanks for the kind words!> I have a screwy tank population and I need advice on how bad it really is and if I can intro a livebearing species into it.  I have a 29 gal long tank with an AquaClear 200 filter and a heater. For livestock I have 2 Plecos, 1 banjo catfish, 1 dwarf frog, 1 Kuhli loach (sp?), <Kuhli> 1 Oranda, <Does NOT belong in this tropical mix at all.> 6 tetras (maybe serpae or phantom) , 5 small mystery tetras-3/4 inch white with 2 red spots on fins, and 6 Cory cats. I had a school of black sailfin mollies-about 9 as well. <Too many fish, including the mollies.  Mollies prefer harder, more alkaline water than the tetras, banjo, loach, plec, Corys....> I keep the tank at 78 degrees, I add 1tbsp of salt for every 5 gallons and I test it every 2 days. I do a 10 gallon water change 2-3 times a week <Slow down there, turbo, that's a bit too much changing of water!  Kick back and enjoy your tank a bit.> and the ph is always around 7.8, <Too high in my opinion for the most of your fish - BUT - a stable pH is what's important, NOT a precise pH....  I would keep this as-is, if it's working well for your fish.> ammonia zero, nitrites and nitrates negligible. <Mm, nitrites should not be "negligible", but zero.> Half of the mollies were a new intro and I think they stressed out the original mollies. After 2 days together I saw one male start to lose weight and move to the bottom of the tank and start shimmying. <Not a good sign, at all....> He died. Another one became sick the next day and I took him to the pet store for advice. They said he was going to die so I left him there. <Could be salvageable - I have seen these symptoms in plenty of livebearing fishes before; in my case(s), it was always Oodinium ("velvet") - a pretty communicable parasitic complaint.  Uhh, you really, really should start employing a quarantine tank for new livestock....> I came home and Moved the 5 new mollies out of my 29 and added a little more salt. The new mollies are doing ok-1 fatality and all of my original mollies are dead. Before they die they develop a faded cast on the back half of their body. What went wrong? <Yes, I imagine you saw some sort of protozoan parasitic disease.> What should I do? <In all honesty, I did have some great success treating exclusively with food medicated with Metronidazole - but there are more effective methods of treatment, to be sure....  just none I would comfortably use in the presence of your scaleless catfishes and sensitive tetras.  Oh, actually, I take that back - elevated temperature and salt (perhaps bringing the specific gravity of the water up to even 1.003) would likely bring about a cure, and though somewhat irritating to the catfishes, is certainly better than dying.> I lost my little girls pregnant molly in this mess and she's very upset-can we get another livebearer? <I would not, not in this system.  Too differing in water preferences....  Why not set up a small (say, 10g or so) tank for her for a few platies?  If you have the space, time, funds to do so, of course.  I would keep such a tank salted a bit more than your current tank, and perhaps even buffer the water with a little bit of aragonite sand or crushed coral in a filter sock in the filter to keep the pH a little high and stable.> And if so-what do you suggest? Thanks so much! Any advice is appreciated. Lynn Fish <All the best,  -Sabrina>

Platy Killers  10/2/05 Dear Team, <Catherine today> I wonder if you can answer this, we have three Platies in our aquarium and they have just killed three of our other fish.  Can you give me any idea of why this may have happened.  <Not without a bit more information.  What kind of fish?  How big is the tank?  How old is the tank?  Why do you assume the platies killed the other fish?> Stephen F. Ellis  <Catherine>

Mollies and Tetras 7/15/05 My female molly just had her babies this Monday. I asked my friend if she would like some of the babies next month, but there was a little flaw in this idea I forgot to see before I asked her if Mollies get along with Tetra's... And well that is the problem... Please help me!   From: Maryjoe Frankruyter <Depends on the species of tetras (Piranha are even tetras!), but most small species do fine with mollies. Bob Fenner>

Re: Mollies and Tetras 7/16/05 I guess I never thought of kit that way really...but I was told that they were about 3 or 4 cm in length and 3 or 4 cm in length is that the size of a piranha!? <Only when young> Also the next email I ask If I do (most likely) Is there a place you know of by Erin, Ontario were I could give or in other terms donate some of the younger mollies to? <Call the local tropical fish stores re> Also I would like to thank you as I have tried to contact many people and ask that but you were the only one to reply so thanks for everything and If you want I can donate some videos of my fish just chilling in the tank happily that you can use on your site!                                          Maryjoe Frankruyter <Mmm, no video thanks. At this point we can't afford the bandwidth. Bob Fenner>

Molly fry with an algae eater? Hello, <Hi! Ananda here this morning...> 2 of my Balloon Mollies gave birth today so I now have a total of about 20 fry.  I have the fry in a 10 gal tank set up just for them. <Please do "over"-filter this tank with a sponge filter rated for at least double the tank volume... frequent feedings = lots of waste.> I was wondering if I could put a algae eater in this tank also or will it eat the fry? <I would be cautious in this regard. If you have algae, it's likely a sign of high nitrates, and fry are more susceptible to poor water quality. You need to change water pretty frequently in a fry tank (think 25% weekly, if not more often, depending on how efficient your filtration is). Also, fry will nibble on some algae. The other concern is the type of "algae eater" you're considering. Some, like the fish commonly called the Chinese algae eater, are okay at eating algae as juveniles, but prefer more meaty fare as adults -- and that meaty fare might extend to sleeping fry. Also, several algae-eating fish will get too big for a 10 gallon tank. IF your tank parameters are not conducive to algae -- nitrates less than 10, phosphates less than 1 -- I might consider something small, IF you also have room too keep it when it has outgrown the tank. Otherwise, manual removal coupled with frequent water changes is probably your best route of action.> Thanks, Robyn <Welcome to molly-world...where they make more...and more...and more.... Do come and visit our freshwater forums at http://wetwebfotos.com/talk !!  --Ananda>

Aggressive Molly Hello! I have a question regarding the behavior of one of my mollies. I have 20 small community fish in a 50 gallon tank, among which are three pairs of differing mollies (black, sunburst, marbled). I just added a beautiful pair of Dalmatian mollies this afternoon to my display tank and I thought they would be fine considering there were no problems with my other mollies. However, one of my male sunburst mollies apparently has taken quite a dislike to both of the newcomers. Is it at least possible that his aggression will subside? <Yes> Is it just due to the fact that the Dalmatians are the "new kids on the block"? <Quite likely so> Or, should I be afraid for their lives and return them? Any help you could provide is appreciated! Thanks, Brody <Well, this is a good-sized system, doesn't sound overcrowded... If it's easy enough to do, I'd catch out the aggressive fish and let it "float" in a fish net, breeding trap, plastic colander... at the surface for a few days... sometimes this gives the other fish a rest, time to mix in with the new dynamic... Bob Fenner> 

Mollies and Snails WWM Crew, First, I must say your site has been very informative. I've learned so much! I have read plenty about Mollies etc, but I have a couple concerns re: my mollies. I currently have 3 of them. 1 silver molly (M), 1 silver lyretail (F), and black molly (F). My concern is with the two silver mollies. I did read that it is not uncommon for the male to chase around the female trying to breed. However my male is NONSTOP harassing the other silver female (she's pregnant too), and rarely messes with the black molly. Is there a special reasoning behind that? <Mmm, no... or not really. Some males are just like this... having more females, more "other" fishes, plants, other decor to break-up the physical environment... helps> I am worried that he will just wear her out, but I don't want to stock my tank with more females as I am already taking care of 16 fry as it is. Any ideas on the best way to handle this randy boy?? hahaha <Isolate him... at least for a while... perhaps in a floating, plastic colander if you don't have another tank> Second question... When is it safe to put the fry back into the larger tank with the adult mollies without the risk of them being eaten? <When they're "big enough" to not be consumed> I have 2 that are about a month old, but I don't want to take them out of the net too prematurely. The others are only a day or two old. Do you judge based on size? or age? <Size> And lastly (are you sick of me yet? haha), about a week and a half ago I noticed a small snail in my tank. Have NO IDEA how it got there as I sure didn't buy one from the store!! Then, when doing a water change the other, came across ANOTHER one that was twice it's size. I'm assuming it was under gravel somewhere because there's no way you could miss it otherwise! How do I know if it's ok to keep in the tank and breeding of snails etc?? I do NOT want more snails!! I have looked at the info on this site re: snails, and haven't come across one that looks like mine. Is it better to wait till they're more grown to determine the type of snail? And just out of curiosity... any ideas on how snails got in my tank? <Come in... with fish purchases in the water, some live foods... can be eliminated in a few ways, but not likely a problem... perhaps a help in keeping your tank clean... Not harmful to your fishes> Is it possible they hitched a ride on the fish as tiny lil thingies on them? Sounds crazy but, I have no other clue as to their appearance!  Thank you so much in advance for any help you can give! I will continue to research your site for more information. It's a great tool!! Sarah <Thank you for being part of it. Bob Fenner> 

Molly chums? (1/15/04) <Hi! Ananda here today...> We've had a tank for years and years... a few weeks ago we got three mollies....two males and a female.   <It's generally better to get multiple females per male, so that each female gets a bit of a break from the males' attentions.> One of the males is acting very "spazzy"  (my son has named him Spaz!) He never seems to sit still, he is always kind of jerking back and forth. <My mollies are almost always moving, but the jerking back and forth isn't a healthy thing. I occasionally see that in mollies that are in one of the freshwater tanks. My usual way of dealing with that is moving the affected fish into the light-brackish tank. If you are running these in a strictly freshwater tank, you might consider adding just a bit of salt (on the order of 1 tablespoon per 10 gallons).> He is very chummy with the female molly....they are now hanging down in the bottom back of the tank together.... I was wondering, is this some sort of mating ritual???   <Not one that I've seen. "Anytime the lights are on, anyplace in the tank" seems to be the motto of the males I've got. The one ritual I do see is that the males will raise their sailfin and swim in circles around the female, as if to say "Look at my pretty fin! I'm so gorgeous! You really do want to have my fry, don't you?"> ...or is something wrong with this guy?? ....desire or disease?? HA!   <Mollies really need hard water and a pH above 7.2, or a brackish system, if they're going to thrive. (Even in my planted tank, my pH is around 7.8 and the hardness is around 12.) If your water is too acidic or too soft, you might consider a brackish tank for them.> Thank you!  ~Wendy and Levi <You're welcome. --Ananda>

Re: Molly chums (01/15/04) Thank you Ananda!   Sometimes all it takes for a problem to fix itself is address it....! <Yup, seems like that's the way it works sometimes.> This morning when we woke up, he was back to normal.....we've decided to still call him Spaz though! Thanks for your fast response!  Look forward to visiting your site some more!  ~Wen <Cool. Check out the forums, too: http://wetwebfotos.com/talk ... often, you can get a faster response on the forum, because we don't have to wait for email transit time! --Ananda>

Companions For Mollies Hi crew, We have a 10g freshwater tank set up with three live plants and gravel, some granite rocks, heater (78 degrees usually), AquaClear filter etc. Water quality consistently excellent after spiking after about one month. For nearly three months we have had one female Dalmatian molly and two male guppies. Everyone growing and healthy, and happy except at feeding time when the molly chases the guppies away from the food. My question is what and how many others could we add? We have five Molly fry two weeks-old in the same tank but in a partitioned area, looking healthy (a number were found dead and we have given away three). My kids would like to add two aquatic frogs, a catfish, another male guppy and keep a few of the fry. Is this realistic given the size of the tank? Do you have a recommendation re. a catfish type that is compatible with mollies and molly conditions e.g.. warm with some salt in the water)? We are looking for something quite different from the other inhabitants that can have a role in cleaning the tank and (hopefully) eating tiny snails (which I currently vacuum out with water changes). Thank you! from Andrea, Carter and Elizabeth. <<Hello. Congrats on the tank :) Sounds like things are going well. I do feel the tank will be a bit overcrowded if you add the fish you are contemplating, yes. The best way to know is to test for nitrates. A good nitrate test kit will tell you if your bioload is too high. By regular testing and water changes, you should be able to keep the level stable, say at around 40ppm (for example). If you do a water change per week, but you can't keep the nitrates down at 40ppm, then you have too many animals in the tank. Keep in mind the nitrates will get higher as the fish grow...As for compatibility, some mollies can be aggressive. If the guppies start to lose tail finnage, you can probably blame the mollies. The mollies may also decide the frogs make good eating...and as to the frogs, please make sure you buy the actual Dwarf frogs, not African Clawed frogs. They are hard to tell apart when small, but the clawed frogs will have no webbing between their front toes. Clawed frogs grow quite large, the size of your fist. As for a compatible catfish...normally I would say Corydoras or Otocinclus for such a small tank, but given the mollies and salt, it's a bit harder. I believe you would be better off to add a lace catfish, (Synodontis nigriventris) if you can find one at your LFS. They are quite pretty, grow to about 2-3 inches, and swim upside down all the time. Interesting addition to a community tank. They will "hover: beneath the leaves of your plants: http://www.scotcat.com/factsheets/s_nigriventris.htm  My last bit of advice to you is...save up for a bigger tank. You appear to be a true hobbyist! :) -Gwen>>

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