Please visit our Sponsors
FAQs on Silver Dollars 1 

Related Articles: Serrasalmine Fishes, Piranhas, Characoids/Tetras & Relatives

FAQs on: Silver Dollars (Metynnis, Mylossoma, Myleus...spp.) 1, Silver Dollars 2,
FAQs on: Silver Dollar Identification, Silver Dollar Behaviour, Silver Dollar Compatibility, Silver Dollar Stocking/Selection, Silver Dollar Systems, Silver Dollar Feeding, Silver Dollar Health, Silver Dollar Reproduction, Related FAQs:  Serrasalmine Fishes, PiranhasPacus,

Black spots on silver dollar      3/20/20
Hey I have noticed black raised dots on 2 or the 4 silver dollars. They seem fine though. I’m worried about medication because I have a Mbu puffer as well. Is this normal or should I treat?
<Yeah; apparently these are Cercariae, (larval) stage of Flukes/Trematodes... Can be treated for... though are not likely (very) deleterious now that the fish is in captivity. No determinant host to pass on, complete the life cycle. Do read re Trematoda...
If I were the aquarist, I might well do nothing treatment-wise here. Bob Fenner>

Big silver dollars; ID and tips?  11/13/14
.... your email has been rejected by our mail system due to too large file size. See our requirements and re-send
<<Oh! Can/will respond w/o the images>>
Hi fish gurus!
I work at a Petco where every employee is a hobbyist in some animal hobby.
<Ah yes; was a/the "fish" buyer there 91-94. Very good operations staff>
A customer came in with this silver dollar, a smaller comrade, and some angelfish in a 5 gallon bucket, and dropped them off. They'll be adopted out for a small adoption fee (hopefully soon), but until then. They've
been put in the koi tank, since it's the largest tank in the store.
This worries me (I'm sure it upsets you, too!), and I'm wondering if you had any tips for making their time at our store... well... less sad. I'm thinking of blanching lettuce for them (can you do that in a microwave, I wonder?)
We have soft water with a pH of about 7, just straight from the tap. The systems in the store are easily 10 years old, and we do weekly water changes, so I'm not worried about water quality... but I am worried about them living with freakin' koi..!
<Better that water quality is okay than focusing on tankmate issues.>
Am I getting wound up over nothing?
<Likely so>
Our fish guy lives, eats, and breathes fish, but I still wanted to run all this by you guys. ...also, what manner of silver dollar is this dude?
<Need smaller (100's of Kbytes) pix of high resolution...>
S/he's darn cute but kinda stressed out, for obvious reasons (bucket ride, new tank, new people...).
Thanks for doing what you do and putting up with worried fish keepers. <3
-Elspeth "Elf"
<Warm, soft/er, more acidic water is better than the opposite. See WWM re Silver Dollar husbandry. Bob Fenner>

silver dollar tankmates 2/23/11
Dear Crew,
Congratulations on your great job and keep up the good work! I have a 55 gal with 2 overhead filters running. The inhabitants are 6-3" silver dollars (hypsauchen) and a 5" Featherfin catfish. Can I still add some more fishes? If yes, what would look best? A cichlid? Small schooling fish perhaps? What kind?
Thanks a lot
<Hello Carlos, and thanks for the kind words. Silver Dollars in 55 gallons is a bit of a squeeze, and wouldn't ever be my recommendation. Potential cichlid companions for Silver Dollars include such things as Severums, Chocolate Cichlids, Festivums and Blue Acara in soft water, while Rainbow Cichlids, Firemouths and Honduran Red Points should work in harder, more alkaline conditions. More oddball choices could be things like Fire Eels, Tyre-track Eels, Bichirs, Climbing Perch and Pristolepis spp. Cheers, Neale.>

Will different silver dollar species school together? 7/28/10
Hi Crew - I have 4 spotted Metynnis (spotted silver dollars) and wanted to add a couple of normal silver dollars to add variety. Will they school together?
<They'll get along, but there's no guarantee they'll school together. A good rule of thumb is to keep no fewer than five of any one Silver Dollar species. Any fewer and there's always a risk of in-fighting and dominance issues. Of course, your own mileage may vary, and the size of the tank makes a huge difference. Cheers, Neale.>

Molly & Dollar... beh., sys.    1/18/10
I have quite a strange situation going on and I'm honestly not too sure how to go about fixing it.
<Do start by reading here:
Mollies are very misunderstood, and a depressing proportion of them end up dead prematurely.>
Recently, my boyfriend and I purchased a balloon molly as well as a silver dollar. Just the other day we also purchased a 29 gallon tank, so in a week or so we will be getting a few more of each.. the thing is, our molly seems to adore the dollar. Whether or not it's a sign of aggression, I'm honestly not sure.
<It is aggression. I've seen this same thing before with Sailfin Mollies and Australian Rainbowfish.>
Basically what is happening is that our molly is always stuck right next to our dollar. Usually that's all he does, he just sits next to the dollar, occasionally he may kind of rub up against the dollars side.. sometimes though the molly sort of nips at the dollar's side and the dollar may take off suddenly but usually slows down and the molly's right next to his side again.. now the dollar doesn't seem to mind the molly all that much- usually if the molly goes off to pick at some food or whatever, the dollar is right behind him... I've read before that sometimes mollies will nip at
other fish but not in a harmful manner. I'm not sure if this is true but I'm just beginning to wonder how much stress this is causing the dollar, if any at all... I have searched the web and cannot find this same situation happening to anybody else. As I said, in a week or so we will be moving them to a bigger aquarium, I'm just wondering what might happen if we get a few of each.. we were thinking of at least one other dollar, maybe two, but reading this site, it looks as if I'll need more...? Please tell me what you can! As I said, the molly really doesn't seem to cause any harm at all to the dollar- he seems to absolutely adore him.. and to be honest- the dollar doesn't really seem to mind the molly all that much either.. I attached two photos, both of them have each fish together.. the second one is a little tougher to find the dollar but if you look at where the molly's lips are....... I apologize for the lack of quality, I lost my camera so I had to use my phone to take the pictures.. Anyway, please let me know if this is causing stress on either fish or if it will once we purchase a few more! Thanks so much .
<Now, there are two issues here. Firstly, Silver Dollars are schooling fish. They need to be in groups of 5 or more specimens. They also get very big. VERY BIG. So unless you have a 55 gallon tank in the near future, don't keep them. These are big, nervous, herbivorous (eats plants) fish not suited to the average community tank. Now, as for the Molly. Male Mollies fight for dominance by showing off. Essentially they display their size and fins to one another, and the one with the biggest fins wins. What happens if a male Molly is in "solitary" confinement is that he looks for females (finds none) and looks for rival males (finds none). Then he looks for anything that *might* be a Molly. My guess here is that arch-backed fish -- like Australian Rainbows and Silver Dollars -- resemble the silhouette of a male Molly with erect fins. In other words, your Molly thinks the Silver Dollar is another male Molly threatening him. There's no resolution here -- the Silver Dollar can't change his shape -- the male Molly neither beats the Silver Dollar nor gets the Silver Dollar to back down. So the rivalry goes on and on. The two species are not really compatible, so I don't see any point trying to get them to live together. Mollies need very warm, very
hard, basic water, ideally slightly brackish; Silver Dollars want middling temperature, soft, acidic water. Put each in their own aquarium suited to their needs, and your problem goes away. Simple as that. Cheers, Neale.> 

Damaged Silver Dollars; Gobioides broussonnetii in the wrong tank   1/16/10
Hi I have two silver dollar fish with red anal fins.
<Likely the Red-hook Metynnis, or something similar.>
we have had them now for 3 months now and never had a problem , but today I discovered that almost all of ones fins are missing and the other looks like little bites are taken from them.
<Well, two things. Firstly, they can be nipped by other fish. Tiger Barbs and Red-eye Tetras (Moenkhausia sanctaefilomenae) are on the potential list of biters. You've actually made things worse here by keeping these in insufficient numbers; barbs and tetras should be kept in groups of 6+. In smaller groups even the best species can become nasty. It's like getting a potentially lovely dog but then keeping it cooped up indoors all the time.
With the best will in the world, that dog will become frustrated and aggressive. Same thing here. By keeping these fish badly, you've created the conditions for social behaviour problems. Secondly, your Silver Dollars need to be in a bigger group as well. They are extremely social fish, and in small groups their social behaviour goes haywire. Yes, you've guessed it, this can manifest itself as aggression; in other words, fin-nipping.>
I watched them for a few minutes, and saw only one other fish taking interest in them and actually peck at them.
<Problem identified. What are you going to do to fix it?>
the fish was a bleu speckled platy and it is much smaller than the silver dollars I'm not sure of the type of platy it is blue with dark specs on it. are these fish known for such things,
<Some are, yes. But even "good" fish can become nippers when bored or frustrated.>
or do you think the silver dollars have other issues. I have a 80 gal tank and its clean the filter is a fluvial 304.i know there should be more dollars in there but I don't think that's the problem.
<But I think it may well be, and I've been doing this for a LONG time. So hear me out...>
and they have never showed any aggression towards each other there are about 27 other fish in there
2 tiger barbs
<Nippy; 6+ specimens.>
3 sword tails
<Males are aggressive.>
1 Danio
<6+ specimens; can be nasty when bored.>
3 angel fish
2 blood fins
<6+ specimens>
2 red eyes
<Nippy; 6+ specimens.>
3 gold fish
<<Need to be elsewhere RMF>>
2 African butterfly
1 6 inch dragon fish
<If this fish is Gobioides broussonnetii, and I think it is, it's a BRACKISH water fish and is doomed to die in a freshwater aquarium. Surely you didn't buy such an unusual fish without reading up on its needs first?
Either you did that, which was bad enough, or you ignored the advice you'd seen about it, which is even worse! Cannot be kept with any of these fish, except perhaps the Guppies, which will do just fine in a brackish water aquarium at the requisite SG 1.005 (about 9 grammes marine salt mix per litre). Note that adding a teaspoon of salt per gallon will not help one bit; adding enough salt for this Goby will quickly kill all the other fish in this tank, except for the Guppies.>
1 blue platy
3 pearl gouramis
1 blue Gourami
1 fire tail guppy
all these fish are much smaller than the silver dollars except the dragon but its totally non aggressive.
<Indeed. Gobioides broussonnetii is a lovely fish. It's a shame it's so often bought by people who insist on not researching its needs prior to purchase or decide for whatever reason not to keep it the way it should be kept.>
Any help would be greatly appreciated.
<Up the numbers of the fish being kept, removing surplus fish as required to make space. Transfer the Gobioides broussonnetii to a brackish water aquarium.>
please and thank you in advance
<Happy to help. Cheers, Neale.>

Silver dollars fighting 10/7/2009
I have four silver dollars
<Groups of six or more, please.>
in a 72 gal. They have been together a little over two months. (Other fish: 7 Serpae tetras (starters), 1 turquoise rainbow-3.5", 1 male pearl gourami-4"-starting to become more feisty, 1 platy-2"(starter), 1 bushy nose pleco-4", 1 clown pleco-2.5", 3 bamboo shrimp).
<An interesting mix of fish. Serpae Tetras tend to be nippy, so watch them carefully. The others should be fine, though it goes without saying that as schooling fish, Rainbows are happier in mixed sex groups of six or more.>
The tank has been running almost 5 months and the water quality is good. I do a 10-15% water change weekly, run two 350 Marineland filters, keep the temp. at 79. Two of the silver dollars have red anal fins (I guess they are called anal fins, they are the fins underneath the fish towards the back),
and the other 2 don't really have any color on their anal fins.
<Hmm... if these are Metynnis argenteus or some other Metynnis spp., then it's the males that have red anal fins.>
One of the red anal fins is 4" in diameter and the other is about 3.5". The other 2 have the same measurements. About a month and a half ago, the two colorless ones developed 2 black spots on their sides and the edges of their tail fins/top fins also turned black.
<Do look at Metynnis maculatus, which has black spots on its flanks.
Metynnis argenteus sometimes has very small speckles on its flanks, but not really big spots. Metynnis lippincottianus is another option too; while similar to Metynnis argenteus, it tends to have bigger spots on its flanks. Myleus rubripinnis is also sold as the Silver Dollar sometimes, though its red, hook-shaped anal fin should help tell it apart. Spend a little time on Google comparing photos. While I'd be surprised if you had multiple species in one batch of fish, it's not impossible.>
They have been acting more aggressive towards the other 2 silver dollar, with the bigger one being the most aggressive. These two have often been rubbing against one another. I'm confused, I thought the ones with the red anal fins were the males, but they get chased into corners and they stay out of it when the other 2 are rubbing and fighting.
<Well, yes, the ones with red fins usually are males if we're talking about Metynnis argenteus.>
Are the 2 with the black spots both males fighting for dominance, or male and female?
<Difficult to say. When kept in groups less than six, "all bets are off" when it comes to behaviour: schooling fish simply don't work as they should in too-small groups. In a nutshell, schooling fish try to establish a pecking order. In big groups, no one fish can bully all the others all the time, so a sort of peace reigns. But if you have too few, you make it easy for a bully to cause trouble, and their schooling instinct doesn't work.
Try adding some more and see what happens.>
They are often going at it while the other 2 pick a corner until it's calm again. I have also noticed that the 2 with black spots will periodically go over to the other silver dollars and nudge or nip at it, then go off again to rub and fight. This has been going on for the past 2 months. I assume it is some kind of breeding behavior, but shouldn't it be over with by now? I have not seen any eggs, will they just keep going until some eggs are deposited.? I wasn't to concerned before, however, now I'm starting to see more ragged fins with no end in site. Should I let the behavior run its course, or do I need to do something?
<Do something.>
Thanks for any info
<Cheers, Neale.>
Re: silver dollars fighting 10/7/2009

Thanks for the quick response,
The tetras have been behaving and only fight amongst themselves and the Gourami has taken over the tank.
<Well, okay.>
The Gourami doesn't beat up any one fish but they all know whose boss.
<For now.>
I attached a few photos, maybe they can help with identification.
<Actually, they look rather odd, and not any species I'm familiar with.
Myleus schomburgkii has a black vertical band on the flanks, but a bit further back along the body. They certainly aren't the Red-Hook Metynnis, Myloplus rubripinnis; the anal fin is all wrong for them. The two common Silver Dollars, Metynnis hypsauchen and Metynnis argenteus, have the right body shape and the red anal fin, but not the spots on the shoulder like yours. Metynnis maculatus has lots of spots, all over its body.>
The two that develop the spots (also red throats and black edges on fins) don't always them. They seem to change almost instantly when they are ready to do battle, which most of the time during the day. I was afraid of adding more because I didn't know if there was enough room left. I'm not getting a bigger tank any time soon, however, if adding more with bring peace, then I'll do it.
<I suspect adding a couple more will be helpful.>
Thanks again
<Cheers, Neale.>

All plastic plants... I'd feed some greens. RMF

Re: silver dollars fighting  10/9/09
I plan to pick up 2 more silvers dollars. If there is a selection, should I get 2 like the aggressive ones with the spots or 2 like the others? Does it matter?
<I'd get two of the *less aggressive* sort, on the assumption this will minimise bullying by dividing up the attentions of the aggressive fish among a larger number of non-aggressive fish. Cheers, Neale.>
Re: silver dollars fighting  10/22/09

hello again,
I recently added two more silver dollar. The store had one large red hook and three small common ones. I bought two of the common ones. They are only about a fifth the size of my current guys. They haven't schooled with my big guys yet, but they are starting to become more comfortable.
<Only members of the same species school, so it's important to make sure you buy the same kind as whichever ones you already have.>
The turquoise rainbowfish is bossing them around a bit. He doesn't nip, he's just pushy. I guess he wants to show them that he was there first and he's bigger and badder.
<Rainbowfish should be kept in schools as well, and kept singly, yes, their behaviour can be aberrant.>
The first day they were in corners, now they just move when he comes by then go back to doing what they doing. I was wondering if I could add one more fish - an angelfish.
<I wouldn't mix Angels with Serpae Tetras; Serpae Tetras are notorious fin-nippers, and I wouldn't ever keep them in a community tank. These were my first ever tropical fish -- and I learned about their shortcomings the hard way!>
Would the pearl Gourami not like that?
<Usually, Gouramis and Angels get along fine, given adequate space.>
Would the angelfish become a problem as it grows?
<Pairs certainly become territorial, and single mature males possibly so, though not usually.>
I'm looking to add one more nice looking fish, the angelfish fits that description. If the angelfish wouldn't be a good idea, do you know of one that would work?
here's my community again: 6 silver dollars-4.5",4",2@3.5",2@1.5", 7 long-fin Serpae tetras, 1 turquoise rainbow-3.5", 1 male pearl gourami-4", 1 platy-2", 1 bushy nose pleco-4", 1 clown pleco-2.5", 3 bamboo
<Hope this helps, Neale.>
Re: silver dollars fighting  10/27/09

me again,
<Hello Curtis,>
I had to remove my turquoise rainbow fish. I put him in my 10 gal.
quarantine tank. He immediately attacked the 2 new small silver dollars, then preceded to harass 3 of the other 4 silver dollars. I had noticed him hanging with my silver dollars lately. Maybe he thinks he's a part of their group. Anyway, he would not let the 2 new guys school with the other 4.
When I removed him, the 2 new guys looked so relieved they explored every corner of the tank and began mingling with the big guys and the big guys immediately started becoming more friendly to one an other.
<Yikes! Sounds quite the disaster story.>
What do I do about the rainbowfish? I would really like to keep it - it looks quite nice, but I don't want a rampaging fish. I would consider selling it. Would it calm down after a few weeks in quarantine?
<Often this does indeed happen. As Bob says, "a spell in solitary takes the fight out of them". Put in more biological terms, he's removed from the social group and from a familiar environment. When returned, he has to re-learn his position in the pecking order, and usually the fish that are already there will have the advantage. So yes, it's well worth a shot.>
or go back on the attack? I'm at my stocking limit as far as the inch per gallon rule goes, so I don't have room for 5 more.
<Indeed, adding a few more, maybe even 3-4, would help.>
<Cheers, Neale.>

Who "nose"? (I love puns), Silver Dollar hlth.   6/28/09
Good evening!
I came across your website and I am very pleased with what I have found!
This site is VERY informative with great tips for keeping/breeding fish! I made an attempt at the flow-chart for diagnosing a diseased fish and that is where I hit a road block.
We have a silver dollar fish who eats normally, acts normally, gets along well with the other fish, but it looks like his nose is growing outward. I thought it was a parasite, but to me it just seemed very odd for a parasite to live in a fish for 2+ years that only affects its "nose". From the side, it looks like he (or she) has a really bad over-bite.
Do you have any suggestions as to what this is, how it got there, and how I can treat it? It doesn't seem to bother the fish, I just feel bad because he's like Pinocchio while the other silver dollar fish is just fine.
Thank you so much!
<Cathy, without a photo, it's impossible to be sure what's going on here.
Yes, it may simply be a genetic abnormality, one jaw being bigger than the other. This would certainly be consistent with a fish having these symptoms but otherwise living a long and happy life. Columnaris infections
(sometimes called, misleading, Mouth Fungus, despite being caused by bacteria) can also produce lumps and lesions around the mouth, hence the common name. These usually look like grey to off-white masses of mould, so should be fairly obvious, and they're generally fatal within a period of a few weeks, tops. So while Columnaris might be an explanation if this suddenly came out of nowhere, if your fish has been like this for years, Columnaris probably isn't to blame. Fish Pox (which looks like candle wax) and Lymphocystis (coffee-coloured textured lumps) are two outside options, but neither are common among characins. Cheers, Neale.>

Silver dollars not eating   5/13/09
<Service to you!>
I have a problem with silver dollars not eating. In three weeks they have only eaten once, as far as I can tell.
I have a 90 gallon tank with an 8 inch Oscar, 6 inch cichlid of some kind,
<Oh! These might well be psychologically malaffecting your Dollars>
who are both doing well, and 3 silver dollars. Yes, I know I should probably have at least 6 silver dollars, but I do not.
<Three are fine here>
There is an established pecking order, with Oscar on top and dollars on the bottom.
The dollars do get pushed around but are not really attacked or bitten, just chased a bit.
I have not turned a light on over the tank at all since they have been here. I do water changes weekly, and I change the filter components as specified. The filter is overhanging, said to be good up to 110 gallons.
<You really could use more... Much more here>
I raised the temperature a couple degrees recently, only because one web page mentioned it may help (although I didn't really believe it would) - the temp is usually at 75 but now up to 79, using one heater.
<I'd use two here... and hide from the cichlids>
I have had the dollars for 3 weeks and they have only eaten once. They have ample opportunity to eat, as I distract the other fish while attempting to feed the dollars (Oscar loves to hang out with me). I have tried floating flakes and pellets, like they were fed in the pet store, as well as sinking cubes of thawed omnivore food ( a mix of brine shrimp, plankton, veggies), beef hearts, krill, and even hand picked and chopped earthworms. They simply ignore the food as it floats in front of their face and sits on the bottom near them. I plan on getting a floating live plant, in the hopes they will munch on that. My guess is the Oscar will tear it apart but who knows. I cannot feed them at the surface as they seem to be more scared of me than the other fish. They are usually swimming about when I get home from school, but hide in the corner when I am in the room. They looked healthy when I bought them, seemed to adjust well, ate for the first time a few days after I put them in the tank, but have not eaten since. They still look relatively healthy, but show signs of deterioration. One seems more pink-ish now than silver, and kind of seems to have his head caving in.
<A very bad sign... of starvation>
I would love to keep them, but they seem to hate their life. Any ideas on how I can entice them to eat?
Meghan Moran
Masters Graduate Student
Crop Science, University of Guelph
<More a matter of incompatibility than feeding here. These S. American Characoids need to be placed elsewhere... Apart from the "terrifying" cichlids... Another co-factor might be water quality... They do prefer even warmer water... and soft, acidic conditions as well... But do move them to another system in any case, and soon. Bob Fenner>
Re: silver dollars not eating 5/13/09

Thanks. I got that done...borrowed a tank, set it up, had the water checked, got the go ahead to transfer the dollars.
<Ah, good>
Sad state of affairs indeed. I hope they recover, then I suppose I'll have to find someone to take them. Thanks for your time
Meghan Moran
<Thank you for this follow-up, and caring, being human to make this prompt change. BobF>
Re: silver dollars not eating 5/15/09

Thanks. Your response made me feel a bit better. I feel guilty and I feel terrible for the fish. The first day in quarantine and they didn't eat. Any special way to entice them or particularly tasty treat that would be irresistible?
<Yes... palatable plant material... something like
Egeria/Elodea/"Anacharis" and warm water (low 80's F)>
Now I also noticed the Oscar has Ich, must have just set in/become visible.
My problem is the quarantine tank is in use! Would being in a Rubbermaid bin or other such plastic container stress the Oscar out if he can't see out of it?
<... See WWM re... I'd just raise the temp. where the fish is>
I don't know what to do, I don't have a third tank. How long does it take to treat the Ich?
<... See...>
I'm sure that length of time can vary.. I just feel awful about this whole thing, I want them to be healthy.
Meghan Moran
<I want you to use WWM. B>
Re: silver dollars not eating 5/15/09

You're right, usually I check all the articles first. Thanks for your time :)
Meghan Moran
<Ah, good. BobF> 

Cichlid in need of help
Parrot Cichlid Getting Intimidated By Silver Dollar  4/14/09

Hello, My name is Suzanne. I have a cichlid that's in need of help. He's bright orange (solid color, no spots), about 4 inches long- I don't know what type he is.
< He is called a parrot cichlid. This is not a true species but a cross.>
We've had him for approximately 3 years and he's never been sick.. until now. Our cichlid has lived alone in well- taken care of 46 gallon tank for the last 2;5 years. About a week ago, we introduced two silver dollar fish, which the people at the aquarium store recommended. The cichlid and the silver dollars were fine for the first few days. A bit of fighting.. The cichlid jabbed the silver dollars in the eye. Our cichlid got a torn fin. I've been putting "Melafix" into the water to speed up the healing process. But the real problem started about 3 days ago. One morning I woke up and the cichlid was lying upright (meaning not upside down or sideways, just upright, except not swimming) in a shell that was recently placed in the tank. He has been lying in that shell and hardly ever leaving it ever since then. When I approach the tank, he comes out, swims,
and looks fine overall. His color has not changed, he has an appetite, there are no strange spots (except a very miniscule black spot on his head). When he swims, at times he seems absolutely fine.
Other times, it looks like he's putting a tremendous amount of energy into swimming, but he doesn't seem to move very far. It even looks like he's twitching sometimes. Very spastic. Other times when he leaves the shell (which is rare), he hangs out on the floor of the tank and eventually, starts looking unsteady, and veers onto his side momentarily. Inevitably, he returns to the shell and stays there.
I'm not sure, but he looks like he's breathing heavy. It's hard to tell. The silver dollars seem absolutely fine. They're swimming around and look very healthy. They're not bothering the cichlid anymore at all. They pretty much leave him alone when he comes..
maybe approaching him a bit, but it doesn't seem particularly aggressive.
We checked the water levels. The pH, nitrite and ammonia levels were fine. The nitrate levels were slightly elevated. We changed 1/3 of the water, cleaned the filter (but didn't clean/change the little cylindrical pieces in the filter, or the pellets- to not over-clean), suctioned the gravel, and changed the air pump so that now the bubbles it generates are considerably stronger than before. The water temperature is at approximately 89 degrees.
< Way too warm. Lower to 78-80 F>
He looks completely catatonic, although again, there don't seem to be any other obvious signs in terms of his color, appetite or otherwise that indicate illness. Is it behavioral? That seems crazy.. but it crossed my mind
that perhaps he feels really aggressive towards the other fish and is avoiding them. Or could it be his fin that's bothering him? Or is he really sick? Any advice/suggestions/resources would be a tremendous
help. Thanks so much. Suzanne
< Thanks for the photos. They were very helpful. The silver dollars have ganged up on your parrot cichlid. He is now very stressed and may have an internal bacterial infection. This cichlid cross does not defend himself very well and is easily picked on by other fish. If the silver dollars are removed he may swim normally. If the silver dollars are removed and he's still has a swimming problem then there probably is an internal infection.
You fish will not get better with the silver dollars in there. Once they are removed treat with a combination of Nitrofuranace and Metronidazole. This may cause some ammonia spikes because the antibiotics may affect the biological filtration.-Chuck>

Re: cichlid in need of help
Cichlid Intimidated By School Of Silver Dollars 4/18/09

Hi Chuck, I just wanted to thank you for your advice. I removed the silver dollars right away and bought the recommended medicines in case there was a need for them. The Silver dollars have been out of the tank for
less than 24 hours, and our parrot cichlid has already begun to swim around and is looking much more active. I'm not sure yet, but I think it might have been just what you suggested- severe intimidation. I'm
keeping an eye and seeing how things progress before I introduce the medicine. Thanks very much again! (By the way, I typed the wrong temperature of the tank when I wrote to you initially. The temperature
was in fact around 78 degrees.. thankfully not 89 degrees!)
All the best, Suzanne
<Glad everything worked out ok and no medication was needed.-Chuck>

Silver Dollar Fish spots and possibly bad water.  1/4/09 Hi, I recently discovered your site and my head is spinning from all the recommends and good information! I wrote you this week to ask about my Gourami's nipped fin and you were extremely helpful. Now I have just discovered I probably have two new problems. My Silver Dollars appear to be developing spots. They are round dark gray spots that don't seem to change the fish surface texture in any way. See the attached pictures. The fish appear healthy in every other way; good social life and very good appetites. And I really thought my tank was cycled, but it's not and I'm fearing for the safety of the fish. I relied upon unreliable chemical measurement devices; quick dips. And used a lot of chemical products. Now, I'm wondering if my two problems could be the same problem--bad tank water causing Silver Dollar spots. All my other fish are doing well, except for one of the Cory cats who is obviously very lonely; eats well, but hides a lot. But I won't add more fish until all these problems are resolved. To sum up, here are My Questions 1. What do my Silver Dollars have? 2. How do I fix whatever it is they have? 3. Where did I go wrong with tank upgrade cycling? 4. How do I fix the tank upgrade cycling situation? The Story. I thought the spots were natural coloring on the two largest of my Silver Dollars; I have three of them. Then today I visited my LFS and spent some time observing their Silver Dollars--none of them had spots. When I returned home, I noticed the smallest of my three now had spots when there hadn't been any before. Plus I realized the spots on the other two had become more numerous. I guess that means it's more than natural coloring. I'd like to know if this is a sort of disease and what I can do about it. General information regarding the tank is below. But here is some history that can be helpful in diagnosis, I hope. A month ago, I upgraded from a 10 gallon tank to a 50 gallon tank. To cycle the new water, I transferred about 7 gallons of water from the 10-gallon tank into the new 50-gallon tank, inserted filter material from the 10-gallon tank into the new tank filter system and used the Stability product (described below) as directed--except I extended it's use from one week to two & a half weeks. So as to let the good bacteria build up, I've only done one partial water change with the new tank--I vacuumed the bottom and changed out about five gallons of water. I'm wondering if my Silver Dollars have a bacterial infection from overuse of the Stability product. But that's confusing because the bottle specifically stated there was no danger in over use. Stability-New Tank Stabilization System. What follows is a quote from the bottle. "a synergistic blend of aerobic, anaerobic and facultative bacteria which facilitate the breakdown of waste organics, ammonia, nitrite, and nitrate. The bacteria employed by Stability are non-sulfur fixing and will not produce toxic hydrogen sulfide. Stability is completely harmless to all aquatic organisms as well as aquatic plants, thus there is no danger of over use." Using the quick-dip test sticks left over from my smaller tank, I thought my upgraded tank was cycled. After reading your web site I decided a more precise measure of tank chemicals was in order and bought some test kits today, (that's what I was doing at the LFS). I learned two things. One, the color charts on these kits are very hard to read. Two, my tank has NOT cycled. I obtained the following readings. Nitrite NO2 = 1.0 ppm NO3 = 5.0 ppm So now I'm thinking maybe the Silver Dollars have been stressed out all this time and the stress led to the development of a bacterial infection OR that the high level of NO2 has done something to the fish. I really thought adding the old water from the 10-gallon tank and old filter material would have sped the cycling process along. The final thing I can think of is that I had a ph problem for 4-6 weeks, the water was acidic, around 6.2. About one and a half weeks ago, two heavy doses (about 5 days apart) of a ph regulator brought it up to 7. Could the spots be related to water acidity? After much reading on WWM I've decided I'm probably overfeeding and will reduce feedings to one type of food once daily and cut out the proteinaceous shrimp until tank properly cycles. My LFS owner told me that my fish will survive the high NO2 and NO3 and that the tank will probably finish the cycling within 2 or 3 days. I'm not as confident as he is and am worried about the toxicity of my tank and the health of the fish in it. Tank information. 50 gallon tank: 19" high, 48" long, 12" wide; Ph=7 ; Lots of hiding places-huts/caves/arranged stones; Lots of fake plants of differing texture, height and density; No live plants; Filtration=two Aqua Clear filters, each for 40-70 gallon tank; Temp: 79 degrees; Food: Daily, Aqueon tropical flakes and Hikari tropical micro pellets; weekly, frozen brine shrimp; most days, spinach, romaine lettuce or other nutritious greens. Fish transferred from 10-gallon tank to 50-gallon tank 9 Neon Tetras (one died since) 3 Rainbow Tetras 3 Emperor Tetras 3 Albino Cory Catfish (one died since) Fish added to above fish in 50-Gallon upgrade 1 Pearl Gourami 3 Silver Dollars 3 Buenos Aires <Greetings. The short answer is that several "Silver Dollar" species are on sale, and some of them have black spots. Yours may well be Metynnis maculatus, the Spotted Metynnis, a species that gets to 18 cm in length and according to Fishbase at least is known to give serious bites, so be careful! Silver Dollars are vegetarians to be sure, but they have strong jaws just like their very close relatives the Piranhas. http://www.wetwebmedia.com/FWSubWebIndex/serrasalminae1.htm Anyway, as for cycling. The truth is that these "bacteria in a bottle" products are often very hit-and-miss, and cynic that I am, any product that advertises itself with the word "synergistic" rings all kinds of alarm bells with me. It's one of those buzzwords used by marketers rather than engineers most of the time, like "holistic" and "wholesome". So if you went "wrong" anywhere, it was probably in assuming that this product would do what it said it would. The reality of life is that cycling tanks is best done by introducing obviously live biological media -- e.g., live rock (in marine tanks) or mature filter media (all types of tanks). Assuming you have at least one mature filter from the 10 gallon tank, dividing up its biological media into the two large filters on the big tank should jump start them very effectively, and I'd expect these new filters to settle down within a week if "seeded" this way. In the interim, don't feed the fish much (if at all) and do lots of generous water changes to keep nitrite below 0.5 mg/l. With luck, that'll get you through the worst of things, and you'll be fine. Cheers, Neale.> Thank you. There's a wonderful place for you fish-guys in heaven! <What a kind thought! Happy to help, Neale.>


Sick Silver Dollars (no, they're really not!)  8/18/08 Hello Robert I am having some problems again.. You've been extremely helpful in the past.. I have a small shoal of silver dollars, 15 total.. 2-3 of the fish have reddish spots or splotchiness on their bodies. <Normal for sexually mature (male) Myloplus rubripinnis "luna".> 1 in particular has it bad.. They have been that way for approx. 18 months or so.. When I got them I had quarantined for 3 months due to some Ich and what looked to be some sort of secondary infection from the Ich.. The red spots have always been there just less noticeable at times.. 1 fish has it particularly bad.. It hasn't affected his/her behaviour at all. He swims with the rest and eats like crazy.. They are living in a 240 with misc other fish.. Bichirs, Endlis, Distichodus, Niger Cats, Asian Redtail Cats, Assorted Cichla and a large Flagtail Prochilodus.. <Nothing to worry about.> I have attached links to where I have some pics of them saved on the net to reduce the size of this email.. If you want the originals you can take them in whatever size you want from my Flickr link or let me know and I can attach them in whatever size you need.. Thanks Doug Here is the link to the picture set. http://www.flickr.com/photos/fishnfst/sets/72157608166578919/  <Nice photos! Cheers, Neale.>
Re: Sick Silver Dollars (no, they're really not!)   10/19/08
Wow thanks for the quick reply.. I'm glad that they aren't sick :) I saw some with the same markings at the California academy of sciences today.. <Sounds a fun day!> I thought maybe theirs were sick as well.. Now I know... Those are the males... <Indeed.> Thanks Again Neale.. Doug <Happy to help. Enjoy your fish! Cheers, Neale.>

Silver dollars don't look normal Ph 7.6 Ammonia 0 ppm Nitrate 10 ppm or less Temp 77 72 gal bow front aqua clear 300 and two bio wheels The spots on the dorsal fin do not seem normal. There are also larger spots on the skin. These silver dollars approx 4 or 5 inches long. They also appear to be mating. (swimming side by side and fanning their tails rapidly) The attached photo is the same fish full frame if you want to enlarge for a better view. <The parameters you mention may well point to the mis-coloring of the specimens... these fishes prefer acidic water, of no detectable nitrate, and elevated temperatures (the low to mid 80's). Please see here: http://www.wetwebmedia.com/FWSubWebIndex/serrasalminae1.htm I would address the water quality issues... You should see the "redness" disappear with more suitable environment. Bob Fenner> Mike Williams

Silver dollar problems Hi there, I have a question.  I have a 150 gallon tank with 5 silver dollars in it (among others).  One of the silver dollars is very large (6"-7") and very old (7 yrs?), another is just as large and around 5 yrs old, and the others are around 3" and 1 yr old.  Not too long ago I noticed a bump on the side of the oldest one.  It doesn't seem like a swelling or bloating, but more like a small protrusion outward (about the size of a pencil eraser). It is on the lower rear portion of the fish, possibly near the digestive tract.  It grew and grew until it punctured through the side of the silver dollar leaving a decent sized hole, with hard light brown matter coming out every once and a while (not like fecal matter).  It eventually cleared up with no treatment and he looked fine.<probably an infection of some sort... maybe due to poor water quality/nutrition?? Now, the same thing is happening, only to the 5 yr old silver dollar.<would check water quality ASAP. What do you feed your fish?>  I don't want this to keep happening because it sure doesn't look too healthy.<I agree!> Could this be some sort of bacterial infection of the digestive system, or something else like constipation.<Could be an infection of some sort normally they are caused by diminishing water conditions/ or nutrition deficiency> And how do I treat this if I should.<A picture would help greatly since different people observe things differently>I have been feeding them the same food since day one (Tetra Min tropical)<This food is OK>, and have never had this problem.  Thanks for your help and knowledge.<Please try to send a pic...would help greatly and make sure to give me the readings of pH, nitrate, nitrite and ammonia in your aquarium...IanB> -Ryan-

Silver Dollars with torn fins >Hi Bob/crew >>Greetings, Marina for you today. >I currently have 6 Silver Dollars, a Plec, a Bristlenose, a Synodontis eupterus and 2 Pimelodella Pictus in my 125 gal tropical tank.  All the fish get on fine, are eating well and water parameters are correct. However, over the last few months the Silver Dollars have all developed torn fins to varying extents. All the fins are affected on the fish. >>These fish can tend to abrade the heck out of themselves and each other, though the size tank you have them in should be sufficient to avoid this. >The fins actually have pieces missing so I believe the Silver Dollars themselves are doing the damage (it doesn't look like Fin Rot). I have never seen any aggression however. >>It doesn't have to be via aggression, just skittishness.  Have you any rough rockwork in the tank?  Also, set up an infrared light and spy on them at night, you could find a culprit making trouble at night. >My main concern is to repair/heal the damage ASAP but am unsure how to do this other than to continue to feed a quality diet and ensure high water quality. I am also currently using a product containing Tea Tree Oil. None of these measures seems to be having any effect though. >>I would stop using the Tea tree oil, myself.  Until/unless it's proven to do ANYTHING for the fish it's a waste of good money, in my book.  High quality feed will keep them from succumbing to any stress, and my guess is you're spot on about them doing this to themselves.  I find them to often be like high-strung horses, and often wont to bang themselves about.  If you're using any rough rocks, try removing them.  If you feed no live food, offer them some daphnia and mosquito larvae if you can (just about all other freshwater live foods EXCEPT brine shrimp would be good).  Other than that, I would ensure that a full 2/3 of the tank is planted thickly. >Any advice on this would be much appreciated (the Silver Dollars are currently 3.5" approx and growing fast).   Thank you.  Ian Allen >>You're welcome, I do hope this helps.  Good luck!  (Yes, they'll grow quite quickly in such generous housing!)  Marina

Re: Silver Dollars I really want to put aquatic plants in my 55gal but I have 2 Silver Dollars that ate the previous plants I have tried. Do you have any suggestions on a particular species that may not taste good to them?. <Some of the tough Anubias species might do here... and the less palatable Java Moss, Hornwort/Coontail (Ceratophyllum) might be worth trying... otherwise, you might consider building a divider blocking access to the plants (keeping the Silver Dollars separated). Bob Fenner>

Cloudy Eyed Silver Dollar I have a Silver Dollar and her eyes became white, what does it mean? What can I do? Is there something I can buy? <It could mean any number of things. Are the eyes pure white now, mostly cloudy, or just a little cloudy? Causes could be water conditions, external or internal injury, or disease. If it's from poor water conditions then water changes should help. If it's an injury then Melafix may help, if it's from a disease there are commercial medications that your LFS will carry that should help. Please see http://www.wetwebmedia.com/FWSubWebIndex/fwsubwebindex.htm and the FAQ's related to diseases, injuries, and Silver Dollars for more info.>

Silver Dollars I recently converted a 60 gallon tank from salt to fresh. It is currently in the process of cycling.   <Sounds good!> My ultimate goal is to have a school of silver dollars, accompanied by a couple schools of smaller fish such as neon tetras.   <Ultimately, the silver dollars will grow large enough to happily gobble up Neons....  Though they are primarily vegetarians by nature, lunches-with-fins are still lunches-with-fins.> My question is this, assuming I have 8 small 1" fish in this tank, what is the largest school of silver dollars that my tank could support.   <Well, considering that silver dollars top out around 5-6 inches (depending upon what species you get), I would consider than any of those 1" fish would be at risk of being eaten.  But, assuming that they don't, and everyone lives peacefully, and you're not talking about 1" waste factories (baby goldfish, baby Oscars, etc.), I would think three or four adult silver dollars would be comfy in a 60 gallon tank.  While small, you could try more, but you'd have to watch for aggression and thin them down as they grow - and they do grow pretty swiftly.> Thank you for your help.  Dane Sure thing.  Wishing you well,  -Sabrina>

More Silver Dollars! My silver dollars spawned again! I didn't have them in a tank setup for this, I just happened to be in the right spot at the right time to protect the eggs from swordtails with a net and managed to siphon out about ten of them. I don't have another empty tank so I'm attempting to hatch them in a hanging net within the tank the parents are in, and I figure that since the water parameters were good enough for them to spawn, I will touch nothing. <Good idea> The eggs are still currently clear a couple of hours later with a spot in them. My question is: what color will they turn, and how long should it take them to hatch?   <Should remain clear except for the growing juvenile, their eyes... about four days to hatching in the low 80's F... you should be culturing food for them NOW... read about this on the Net... "Rotifer Culture"> -the Pacu kid. (am I just good at keeping the water nice? Or did I just get lucky? I never really do tests on water parameters, I just watch the fish and go with the feel. <Given passable circumstances almost all life will reproduce itself... a high priority eh? Bob Fenner>

Silver Dollars with Popeye Dear WWM Crew (and Mr. Fenner if you're out there) First, Thanks for the help on my first problem which resulted in the deaths of my 10+ year companion silver dollar fish Now I have taken your previous advice and have been aging water and refilling the 55 Gal tank from that. My newest arrivals (5 silver dollars) have been constantly plagued with on problem after another. First - my water here is hard!!, but my previous silver dollar fish lived long - until my water softener changed salt mixes on me which I believe resulted in the "snow storm" that killed off all my fish but the angels. Here's the history: 55 gal tank with hard but clean and regularly changed aged water. 5 Silver dollars, 2 clown Plecos and 3 neon tetras added to tank with 4 gold angels - that had survived the previous 'snow storm'. The silver dollars and neon tetras got Ich shortly after being added to the new tank. Treated with elevated Temp. and salt. No more Ich, but Silver dollars had a white sheen and two of the five silver dollars began bumping along the bottom of the tank and running into things like they were blind. I treated the tank with Pimafix - all the silver dollars recovered. Within a couple of days the silver dollars eyes began to cloud and bulge (pop eye). This has afflicted most or all of the 5 silver dollars. The other fish seem to be unbothered by this affliction, but one neon died and the others were stressed when I added both PimaFix and MelaFix ( I thought I read they could be used together). Pimafix seems to work the best - clearing the eye cloud issue, but the eye bulge continues (several of the silver dollars show the skin area around the eye where it is stretched). This problem seems to go on and on. I read on line that Medi-gold was good for this, but I couldn't find it in my area, so I settled on the next recommended thing (Maracyn-two). While it would be nice to get medicated food, I should state that the Silvers continue to be very active - eating everything in sight - including the pieces of Maracyn-Two tablets that flake off as the tablets dissolve! Do I really need to soak their food in this medication if they are willing to eat it straight? Anyway, I've had these guys since February and they've grown from the size of a US quarter to larger than the top of a soda can. I would hate to lose them now because I'm kind'a getting attached to them. Any suggestions would be appreciated (again). Thanks for all your help. MY previous email (and your response) follows. < South American fish come from soft acidic waters. Many have a difficult time adjusting to the aquarium and to the change in water chemistry. If they don't die outright from the hard water they usually are stressed and are vulnerable to catch all kind of diseases. The later sound like the current problem you are having. Pop-eye is a disease where bacteria build up behind the eye socket. as the bacteria grow and multiply they put pressure on the back of the eye and push it out. I would recommend a 30% water change, vacuum the gravel and clean the filter. Then I would treat the tank with Metronidazole. It is effective on anaerobic bacteria.-Chuck> 

Silver Dollar Compatibility Good day ladies and Gents, I have two Silver Dollars (Metynnis hypsauchen) that have outgrown my tank. They've been together in my tank for two years now. A friend of mine has a 75 Gallon with a mated pair of the same fish, and he said he would gladly take them. I looked through the FAQ's and did not see an answer to my question so I feel safe in asking it.. :) I was just wondering if they're would any aggression between the pairs, and if the tank is large enough? Thank you as usual! Heather <In all likelihood these four will not only get along, but be much happier in a larger grouping... this is how they live in the wild. Bob Fenner> 

Silver Dollars, Environmental Disease - 10/12/05 My silver dollar fish have had on-going fungus that I can't get rid of. It eats up their fins and spreads across their body. I have tried all different Meds for this, and have since stopped treating them to keep from poisoning the tank with many different Meds. The various Meds would seem to cure the fungus, but it comes right back when I stop treating them.  <I imagine this is environmental, not pathogenic.... Let's read on about your system....> I have a 55 Gal with 5 fairly large silver dollars, 4 fairly large angels, 2 clown Plecos, and 2 neon tetras with a knack for survival.  <Tooo many big fish for this tank.> My water is very hard and I've been using peat moss to soften it in a storage container. I'm concerned because my nitrate level has climbed quite high (160), <Disturbing, and toxic if not deadly at this level.> hardness was at 115ppm, ph 7.6, ammonia=0 and nitrite=0. The submersible transfer pump from the storage tank is turned off until I'm ready to transfer water to the fish tank, I first run the water for a short time to clear the pump of the standing water in the pump and tubes so as to run only fresh water into the tank. The storage tank is circulated by an external Emperor filter that I put the peat into. The peat I bought at a Lowe's garden department, doesn't list any additives that I thought would add to Nitrate increase. The 55 Gal. fish tank also uses an Emperor filter for general filtration (but no peat added), and an undergravel filter.  <Consider removing the undergravel filtration - often this is a MAJOR contributor to very high nitrate due to accumulated organic material under the filter plate(s).> All the fish seem to be doing ok except for the silver dollars, although I'm guessing they all may be uncomfortable with the high nitrate level.  <Yes, this level is absolutely staggering. Should be maintained below 20ppm. All the fishes will be affected with time and exposure. This must be rectified.> Very high algae growth also.  <Another bad side affect of high nitrate, overstocking....> I guess I'm questioning if my problems are related to my water storage tank, transfer set-up, or softening process, or something else. <As above, I fear the UGF is the culprit. Test your make-up water storage tank; always be sure to aerate and/or circulate your make-up water if you store it for any length of time (hours, even).> Thanks, John Rogers <Wishing you well, -Sabrina>

Silver Dollars with Fin Damage 8/21/05 I asked for help a while ago with my Silver Dollars looking extremely poorly. Ich causing large sores on their sides, and fin rot, you suggested a Furan based medicine and the continued use of Rid-Ich+. I'm now using Furazone-green (contains: Methylene Blue: 2.5mg, Nitrofurazone (Monofuracin): 122mg, and Furazolidone: 24.4 mg.) and I've doubled the dosage to one capsule twice a day as directed on the package as well as the Rid-Ich+. I've been treating one silver dollar in a ten gallon tank setup with no substrate under my 90 gallon for 10 days now. Figured this was a good location as this is a large, stressful fish and its inside a cabinet. I've noticed the major loss of Ich, and the slowly shrinking sores, but the fins, though no longer discolored, have not seemed to have grown whatsoever. I was wondering what other practices I could take to speed this process, perhaps lowering the ph and adding softer water (distilled percentage)? <After the sores are gone then the disease is practically cured. Now the fish needs to heal. Sometimes the fins get fungused too. These fungused fins to not regenerate. You will need to remove the fish from the water and clip the fins back to past the damaged area. they will then regrow but not as nice as if they were never damaged. Fins diseased back into the caudal peduncle usually do not regenerate.> The ten gallon does have a large filter, in fact its an old, fully cultured penguin 330 Bio-wheel, I shut this down for about 45 minutes every time I add medicine. I'm only changing water when the fish seems to be breathing harder than normal, should I be changing it more often? Any specific help is greatly appreciated. Thanks again!!! < Check the nitrates. The disease causing bacteria continue to thrive when nitrogenous wastes are present.-Chuck>
Silver Dollar Problems 8/21/05
Ok, this makes sense, the silver dollars never had good fins from the day I got them with my used tank purchase, from what I understand they are quite old fish, around 5 years old. But no matter, I'm not too much worried about the way the fins look, as long as the sores close up. How do you suggest restraining the fish out of water? Under a towel, and I imagine this should be done in intervals of just a few seconds. Thanks for replying!!! < If you want to take them out to clip the fins then you take a large soft net and catch them. In a shallow dish you place a clean bath towel that has been soaked in the aquarium water. Catch the fish and place him on the towel and cover him up with only the section you want to work on exposed. Use fingernail clippers to trim the fins back past the damage. Silver dollars have very fine delicate scales that are easily damaged. If the areas get damaged then you might be back to square one.-Chuck>
Silver Dollar Question 8/23/05
One more question please: after the sores are cleared, and their fins are clipped back, do I still have to quarantine them? Or can they go back in the 80 gal? < Put them back into the quarantine tank until the fins start to grow back.-Chuck>

Pop Eye on a Silver Dollar 8/3/05 Hi, I am Janet. I have a 55 gal fresh with 10 white clouds, 4 black tetra, 2 spotted Cory cats, 2 dwarf Gouramis, 1 blue magic dwarf Gourami (the other died in this heyday I have been having) , one goldfish, one black moor, 2 scissortail Rasbora and 2 six or seven year old Silver Dollars that were given to me by a friend when his wife died. They were her babies. Hi Oh Silver came down with Popeye then a god awful case of dropsy. I put in Melafix for the seven day prescribed and Hi Oh didn't really improve much. I changed out 25% of the tank, put in Stress Coat and Stress Zyme and some Methylene Blue. Hi Oh looked bad yet. I went searching on the internet and found your site with salt treatments for these diseases. I didn't have Aquarium Salts but another site said Kosher Salt would do too. So I mixed up the salt (one gal to 4 teasp Kosher salt) popped Hi in and watched him for distress. After 3 min.s (of the 5, unless distressed) I thought he looked like he wanted out. So I put him in the tank. Next morning HE LOST ALL THE POPEYE AND MOST OF THE SWELLING!! I did a test and found my nitrates were 160 so I did another water change out of nearly 50%. Put in Stress Coat and Stress Zyme and Meth blue. My test today shows PH 6.0, Ammonia 0ppm, Nitrite 0ppm and finally, Nitrate 0ppm. It seems Hi Oh is getting Popeye again and I think his pal, Long John Silver is too. Oh, I put in new carbon filters in case of something in the water affected the old new filters I had in. Hi looks great other then that. A very small swelling on his cap (above his eyes/face), looks somewhat silver in most places, eating, swimming all about and with his buddy. My question is should I start over and put the two in a hospital tank and treat with Melafix again or just do salt dips again? How many times can I salt dip a fish and at what frequency.... daily, every other day, ???? Salt seems to best work to bring down swelling. I have been fighting this for 3 weeks now and Hi is still here. He does sit stationary a bit crooked but he swims great. I think he can see yet out of his eyes. So far Long John is puffy in one eye.   This whole mess started with fish from PetSmart and putting their water in my tank. I didn't know not too since I read to do it in a dumb book, only to find out NEVER put water in another tank. I have NEVER tested water before so that is all new to me too but I desperately want to save the boys. Please help me : ( < The high nitrates are stressing your silver dollars. Keeping them down to under 25 ppm will be very beneficial. I have found that salt dose reduce the swelling and some fish do recover enough to be cured from this internal bacterial infection but just don't seem to be cured. I would recommend Metronidazole to treat the infected fish in a hospital tank so it won't affect the good bacteria needed to break down the fish waste.-Chuck>
Silver Dollars Getting Better 8/4/05
Thanks Chuck for the response you gave. I could not figure for the life of me what was causing the problem!! I do have the nitrates (never tested water till all of this happened..... last time I had a fish tank was 1977, didn't test water back then and didn't seem to have any trouble but we would bleed off the tank some every week and change water.) down to 0ppm (Yellow) and Hi Oh and Long John are Popeye free. Hi Oh is over his case of dropsy and is swimming around with Long John and eating food like a vacuum eats dirt. The biggest improvement was always seen after a salt dip and all disappeared after I calmed my nitrates. I REALLY am GRATEFUL that I found your site and read what you said on salt dips and Silver Dollars.  Hi doesn't look quite the same as he did but he is healthy and eating good again. He still is not quite as active as LJ and he is not fully silver anymore but he has had a monstrous 3 weeks and, believe it or not, Long John pesters him till he swims with him. It is the funniest thing I have ever seen a fish do. Thanks again SO MUCH, Janet < Glad things worked out. Thank you for your kind words.-Chuck>

Silver Dollars Looking Poorly 7/16/05 I have four full grown silver dollars that came with my 80 gallon tank when I bought it used. I let the previous dilrod owner  bucket them with the three huge balsa. Well, when I took them out of the bucket, they were beat to hell and back. Ever since they've had body rot, fin rot, lateral line disease, and Ich. I've been dumping medicine in there like crazy (Melafix, PimaFix, and RidIch) as well as keeping the tank as clean as possible. These fish are the only ones with the problem, nobody else in the tank has any disease at all. So I was wondering if this is what they call Neon Tetra disease. or something like that. If so, should I put them down? Or give them away to someone who could rehabilitate them. keeping a fish from getting ill is one thing, but rehabilitating them is another, especially when they are seriously ill. Polara_Blues < Fine scaled characins like silver dollars really get beat up every time they are moved. Use the Rid-Ich to get rid of the Ich as per the directions on the bottle. This is a very good product but needs a little time to work. Once the Ich is gone use a water conditioner that has an additive specifically for wound control. There are many out there. I like Bio-Coat by Marineland. I don't like using the MelaFix and PimaFix to treat diseases because they really seem ineffective and you will need to use antibiotics anyway. If there are signs of bacterial infection like fin rot and open sore on the body then you need to treat. I would recommend using a Furanace type product-Chuck>
Sick Silver Dollars II 7/17/05
Ok, sounds like I was going to wrong way with the medicine. Although I have noticed a considerable drop in fin rot with the MelaFix, it hasn't gone away. < At best this stuff is a bacterial inhibitor.> I'll take your advice seriously. Thanks! <Good Luck.-Chuck>

Silver Dollars - Determining Their Sex Hi Guys - I am getting back into the aquarium hobby after a 10 year hiatus.  This time around, I am interested in the possibility of breeding. <Hey, this isn't a dating service... Oh, you mean fishes... sorry>   I have three small Silver Dollars (smaller than a quarter).   I have the round, all silver variety that has no spots on them. They all seem to have red on their anal fin.  I went back to the store and the other eight in their tank also had red on their anal fin.  I have read that this is how to determine if they are male or female. <Mmm, nope. There are just some species of "dollars" that have red anal fins... in good health, care>   Are all of these males or is there a different way to determine if I have a female in the group of three that I have? <Really only with time, size/growth... and apparent "fullness" of the females... very likely you have both sexes...> I know that I have to wait until they grow up to mate but I would like to possibly determine their sex now rather than having to by an adult female in the future.  Thanks for any assistance.  Mike <Mmm, please see WWM, the Net... re Metynnis, Mylossoma...  species. Bob Fenner>

Silver Dollar Getting Pretty Old  - 09/13/06 Have you ever heard of a silver dollar fish living as long as 40 years?? < That's an old fish.> I have one and has Popeye only in one eye.   I have had this since 1976 and was given to me by someone that claimed to have had this fish for 10 years before me. What is the lifespan of a silver dollar it must be more than 7 years?? < Sounds like you have the record.> I must hold the Guinness book of records with this fish. The fish developed Popeye over a month ago.  I have tried fungus medicine and tetracycline but neither seems to help?   Haven't tried the Epsom salts yet. Please advise. < Do a 50% water change, vacuum the gravel and clean the filter.  Treat with Metronidazole and Nitrofuranace in a hospital tank if you can. If you can't find the medications then try Clout.-Chuck>

Red Hooked Metynnis   6/8/06 I have 3 large red hooked Metynnis.  The old guy or girl has been with me about 20 years. <How nice! Myleus are faves of mine> I feed them a diet of green beans, bananas, lettuce and  Hikari Cichlid Gold medium pellets.  I know this is a long time for a fish to live but just how long have these type of fish been known to live.  If you have time please give a response to me question.   Thanks so much  Jean Smith <I do believe there are some western European public aquariums that have had this species for more than thirty years. Bob Fenner>
Re: Red Hooked Metynnis   6/9/06
Thanks so  much for your reply.  I have mine in a 55 gal tank.  As I said I have the old one, and one that is about l0 years old and a juvenile that I have had about 5 years.  The old ones hook has lost some of the red and it seems to me that his red color has faded some.  I keep hoping that they might spawn. <Would likely need more room...> Also I have two small ones that I bought last year.  They do have big teeth  The two older ones have brown and black markings on them but the young one is still silver.  They are kind of crazy sometimes running into the tank and hurting their noses. <Mmm, again... need bigger quarters>   I just love them!  Again thanks for your reply.   Jean <Thank you for sharing. Bob Fenner>

Silver Dollar with one cloudy eye    6/6/06 Hello Crew <Jasmine> One of my Silver Dollars (I have 5 in total) has one cloudy eye. Water seems to be fine (ammonia=0, nitrite=0, nitrate=10ppm). Being on one eye only, what could be the cause? Is it bacterial or a result of an injury? Thanks Jasmine <Most likely originally the latter, possibly secondarily the former... If this is just "new" I would hold off on actual "treatment"... In all likelihood it will cure of its own accord. Bob Fenner>

Hatchetfish, Silver Dollars, Discus, Compatibility - 05/19/2006 Can one keep Hatchet Fish, Silver Dollar, and a few Discus fish in a 55 gallon tank? <I would not mix silver dollars and discus.  Discus are typically shy and timid, silver dollars are boisterous and perhaps too fast/aggressive.  The discus would likely not get enough to eat in this mix, and would get pretty stressed out.> What do I need for setup if possible?   <Research, mostly.   http://www.wetwebmedia.com/FWSubWebIndex/fwsetupindex.htm > pH?  Ammonia?  Nitrate?   < http://www.wetwebmedia.com/FWSubWebIndex/fwestcycling.htm , http://www.wetwebmedia.com/FWSubWebIndex/fwph,alk.htm > No plants if possible.  Thanks  -Mark <Wishing you well,  -Sabrina>

Fishy Mystery From A Forum Reader - 03/08/2006 I got your email address off the WetWeb website. I have a question and am not a member. <Feel free to join the forums; it's free and fun!> I have 3 silver dollars, I have a 47 gallon tank with a few platies, mollies and tetras. I had a 5 inch rainbow shark and he disappeared as do some of my platies and mollies from time to time. I think when my fish die the other fish eating the body, as sometimes when I clean my tank I'll find something that looks like a skull or fish skin. The man at the fish store said silver dollars are aggressive, I've never read anything bad on the internet about silver dollars. What do you think? <About what, the silver dollars?  Or the mysterious disappearances?  Silver dollars CAN be aggressive.  I very much doubt, though, that they'd be able to take out a sizeable critter like your rainbow shark minnow.  They tend to be a little harsher on plants than fish, but smaller guys like little platies and tetras may get munched.  As for the dying fish, yeah, it is VERY common for active, healthy fish to try to eat a dead or dying tankmate, so that's what's happening with the bodies - the mystery is, what exactly is killing them?  The answer here may be something in terms of water quality.  Please be testing ammonia, nitrite, and nitrate; ammonia and nitrite must be ZERO at all times; nitrate less than 20ppm.  If this is not the case, correct it by doing water changes until the levels are right.  Make sure you use a chlorine/Chloramine neutralizer and match the temperature and pH to that of the tank.  Wishing you well,  -Sabrina>

Tom... need titles to find/match prev. corr... 9/28/06 ? Pacus, Serrasalmine IDs... Tom, <<Hi, Lisa.>> Oh, I'm so confused! Well, my cousin said that I had a cichlid? I know for sure that I had at least one I know for sure is a silver dollar. . . ( I had two) But maybe it's a Pacu? <<Could be... These two, and Piranhas, are sometimes confused at the juvenile stage. As they mature, the differences become more obvious.>> Is there any kind of difference between a Pacu and a Silver Dollar? <<Oh, Lord, yes! Sorry about the emphasis but if you have a Pacu as opposed to a Silver Dollar, you'll need a 300-gallon aquarium to keep it. Not likely, I'm thinking. :) Now, a Piranha might have a distinct taste for your other fish.>> I know for a fact it was eating my fish because one day I saw parts of what was left of my fish chomping on it! I really did get the memo.. Just its wrong.. ( haha) Yes, its very 'nervous' I can't even turn on the light in the tank and it goes crazy. <<Again, this is common of Pacus, which is why they fall into the "tank buster" category. They can/will "frenzy" themselves into anything and everything in the tank. Not what you want in a fish that reaches 30+ inches in length and can weigh upwards of 55 lbs. or more.>> My fish is not typical in any way. Oh, I think this is kind of funny. When I was cleaning my tank I noticed my fake plant had gnawing marks all over them. I wonder who that was from'¦ <<Silver Dollars and Pacus, both, will eat aquarium plants of just about any variety. (There are some plants that folks have found that won't get devoured but most of those that you'll find readily at the fish store will be turned into "lunch" sooner or later.)>> Okay for the filters'¦ even if you have charcoal, they don't get the bad stuff out- thought it got the 'invisible solids' out? <<Activated carbon does a very nice job of "polishing" the water of hard-to-eliminate solids but does nothing for ammonia and nitrites.>> Um, I usually clean the filter when it gets kind of bad. Hard to get the stuff out, I change it. I'm such a bad fish keeper! Definitely getting an F'¦ (haha) I'm guessing you are an aquarist yourself? <<Yes, indeed.>> If so fresh or saltwater? <<Strictly freshwater at this point in time, Lisa.>> Yes, I do wish there was more time in the day. That would be nice'¦ Lately I been going to bed kind of early 9-10. I guess my body isn't in the swing of school yet. Should I tell the person about the worms? Or keep and eye out on the tank? ( I'm scared to tell him.) <<As I suggested, Lisa, the problem is with the tank, not the fish. If your friend's tank comes down with Planaria, it will be due to water conditions in his aquarium, not the fish you gave him. You're off the hook! :)>> I'm sorry I'm bombarding with a lot of questions. Thanks, Lisa <<Any time, Lisa. Tom>>

Silver Dollar dis.?   10/4/06 I have read several of your pages on fish diseases and still have some questions. <Me too> I have a 25 gallon tank which I recently had to drain due to a leak in the top.  I moved all of my fish temporarily into a smaller tank.  I used water drained from my 25 gallon and one of the same filters hoping not to stress anyone too majorly. <Good> I have a 6yr old Silver Dollar about 4inches and 2 smaller ones.  I have 4 Black Skirt Tetra, 3 Rasboras, 2 algae eaters and 2 Longfin zebra Danios.  Everyone seemed fine except the Silver Dollar who seemed to develop a lump on his side which now resembles a small air bubble. <Likely resultant from a physical injury in the move> His tail fin and upper fin then appeared to be torn badly. <Ditto>   I treated the tank with Maracyn and Maracide, as well as Stress coat.  The fins seemed to repair themselves a bit and the swelling on his side went down a little. <Takes time> Then I noticed a small white spot on his upper fin and have started treating the tank again.  This time with Maracyn TC.  I have done frequent water changes.  My ammonia, nitrite and nitrate levels are fine.   <Thus far... do monitor ammonia... the Tetracycline can/will kill off your nitrifiers> This fish eats as well as it ever did.  I would hate to lose him if there is something I can do to save him  Any help you can give is greatly appreciated. Thanks, Sandy <Mmm, the best thing would be to repair (Silastic) the larger tank, move all back there, and wait and see. Should self-repair with good water quality, time going by. Bob Fenner> Re: Silver Dollar   10/5/06 Thanks so much for the response.   I did forget to mention everyone is back at home in the larger tank.  No more leaks..... Now hopefully I can let nature do it's thing, and not over react at ever little spot.....for my fishes sake. Thanks again +) <Ah, yes. Welcome. BobF>

Temperature Range - Metynnis and Rams? Sys., comp. - 09/30/2006 Hello y'all, <Hi.  My apologies for the delay in reply; I've been out, and your email came to us in a format that unfortunately our Webmail system had some trouble with, and I am one of the only folks able to respond to it.> First of all, thanks as usual for your maintenance of a wonderfully informative site. <Thank you very much for these kind words.> (I recently wrote my comprehensive exams for a PhD in education, and cited this site as a great example of a constructivist learning environment. So thanks for your contribution to my degree as well.) <This is high praise indeed - thank you again.> I would like to keep Metynnis hypsauchen and Microgeophagus ramirezi together in a 150 gallon system. <Maybe possible in this size system, given enough plants and hiding spaces....  but do keep in mind that the rapid schooling and darting about of the Metynnis may be stressful to the shy rams.  This is something I, personally, wouldn't try, but I imagine it can be done with success in as large a system as this.> My plan is to keep the temp at about 80-81° F, as this seems to be at the upper limit of the silver dollars and the lower limit of the rams. <The rams can go lower if you don't intend to breed.  Warmer would be preferable for them, but I'm rather concerned about the warm water making the Metynnis even MORE quick and spazzy.> However, I'm concerned that much of the literature about rams stresses that they're delicate, and happier at temps around 85. <Indeed.  But I would not bring the Metynnis to this temperature.> Should I: a) go with the "intersection" temp of 80-81 b) keep the temp higher, on the theory that the silver dollars are more tolerant of out-of-range temps than the rams c) not keep the two species together? <....  I would choose "C".  But again, that's just me.> Thanks again for your help and patience. <And you, again, for your kind words and consideration!> Melinda Johansson <All the best to you,  -Sabrina>

Guppies tails being eaten  -- 07/01/07 Hi, we have a 60 litre tank with several tetras, 2 Silver Dollars, 6 Platys (with a week-old baby in a net cage!) & one Clown Loach. A few days ago we acquired 4 Guppies which we assumed to be male due to their colourful tails. All was fine for the first 2 or three days then, one morning, we found a severely traumatised little person minus tail! We quickly separated him from the others but he died shortly after. We noticed that one of the other Guppy's tails had been nibbled, though not to a great degree, and kept an eye throughout the day. However, yesterday morning, he too had died. Whatever's happening seems to be doing so during the night. Might you be able to advise as we find it so distressing & feel we've done something awfully wrong. Many thanks, Don & Jenny. <Greetings. As you perhaps realise, a 60 litre (16 US gallon) tank is too small for silver dollars. Silver dollars potentially over 10 cm (4") in length and are exceptionally active and fast moving. I'd hesitate to recommend them even for a tank two or three times the size of yours. Clown loaches are schooling fish, and should be kept in at least a trio. Keeping a single specimen isn't very fair to the fish, and you'll probably find it is shy and nervous. Clown loaches are even bigger than silver dollars, and definitely need a bigger tank than yours. For a trio, even a 200 litre tank would be too small. So that's the analysis of your livestock over! Almost certainly the guppies are being nipped by the tetras. Silver dollars generally aren't nippers, so I'd cross those one of the list. But Serpae tetras, black widow tetras, flame tetras, and a few others are regularly implicated. So if you let me know which tetras you have, we can try and identify the culprit. In some cases the problem is too few members of the school, but in other cases the tetra concerned feeds on skin and scales in the wild, so is simply doing what comes natural. Either way, mixing tetras and fancy guppies is almost never a good idea. Even Neons have been known to nip fins under such circumstances! In the meantime, treat for Finrot/fungus. Cheers, Neale.>

Reply... Neale, Don & Jenny... Silver Dollars...    7/2/07 Hi Neale, many thanks for your reply and advice. Our Silver Dollars are about 3-4 inches and seem quite happy. Our Clown Roach 2-3 inches & also seems happy. He/ she is out and about quite a lot from under his log. We intend getting another as we had 2 to start with but one vanished overnight some weeks ago!- but haven't been able to locate a small one. We have a few Neon tetras, 5 Leopards and 4 Blue. Our one remaining Guppy seems unscathed and absolutely fine! Is it possible he might be responsible for the de-finning and ultimate demise of his three amigos? As you've probably surmised, we are novice fish enthusiasts, having started keeping fish at the end of March. Most of our purchases ( Tetras, Platys and, more recently, our unfortunate Guppies) have been the result of advice given by a Fish Specialist shop in Rhyl from whom we also bought our tank & equipment. We have already decided to get a second tank. Ta muchly, Don & Jenny <Hello Don & Jenny! Guppies can be nippy towards one another. Males are aggressive, especially when kept in small groups without females. Whether to the point of killing each other I cannot say. Never heard of that. Possible though. I have no idea what "leopard" tetras are. Never heard of them. Do you mean Leopard Danios? Small, minnow-like fish with spotted bodies that swim blazingly fast? Danios can be pugnacious, and tend to be fairly high energy animals. Work best in groups of 6 or more; any fewer and they often harass their tankmates, not out of malice really, but simply frustration, and the need to chase things and burn off some energy. Blue Tetras are fairly uncommon and I don't have personal experience, but they're said to be peaceful. Neons are not normally nippy but they have been know to bite Siamese fighting fish, so the possibility of nipping a fancy guppy definitely exists. As for questions of "happiness", there's two kinds of happy. There's what works now, and then there's what works in the long term. Your fish quite probably are happy know because they're young. Fish are often adaptable animals and will thrive in less than perfect conditions. But clown loaches and Silver Dollars get big and live for 10+ years, so long term you need a plan. I'd recommend keeping an eye out over the next 6-12 months for a bigger aquarium. There's nothing more miserable than a big clown loach by itself wedged into a too-small aquarium. Clown loaches are notoriously sensitive, sometimes making suicidal jumps out of aquaria when they feel stressed and other times getting Whitespot very easily. Clown loaches are "allergic" to most standard medications, as I trust your retailer told you, and you must never use things like anti-Whitespot potion in a tank with clown loaches. Hope this helps, Neale>

Bacterial Hemorrhagic Septicemia / fin and tail rot  6/30/07 Hello, <Hi there> I have a 16 year old Silver Dollar that has the following conditions. Left pectoral fin is gone; the flap is there and flaps like crazy, but there is no fin attached. <Mmmm, might grow back if not too far gone...> Both pelvic fins are completely gone. The caudal fin is badly frayed (3 weeks ago was almost completely gone) and is strangely red at the base close to the fish body. <Something amiss here...> History; up until 6 weeks or so ago, I had the silver dollar in the tank with a Pacu. <Ohhh> The Pacu was huge and out sized the dollar by ten times at least. One day I noticed that the silver dollar was missing most of its caudal fin and what was there was badly frayed. The pelvic fins were gone as well as was the pectoral. I assumed it was fin and tail rot and treated the tank with Mardel Maracyn Two. The caudal fin began to get better for about a week then went to worse again. <... stress, bullying...> I then thought that it was the Pacu. Although the Pacu never picked on the dollar in my presence I thought it was happening when I was not around. I wanted to get rid of the Pacu any way since it was so big and messy to take care of. I found a home for the Pacu at a LFS adoption tank and that left my dollar to her self. The caudal fin healed from almost nothing to about one-half but then quit and will not heal further. The other fins have not changed at all. I am patient and though that in time all would be well again so went out and bought 3 more silver dollars to keep the old one company. Before getting the new dollars the old one ate well, but now the feeding frenzy and competition is causing the old dollar to swim faster to get her share, but with out the control of all her rudders she cannot aim correctly at the food and misses it. <Provide more bulky food items... greenery that the impaired one can eat easily... Like blanched zucchini> Also, she cannot maneuver well enough to keep up with the other dollars who are younger and smaller. This is causing me to revisit medication or some form of treatment before the dollar winds up dying. <... Medication not advised here> My tank is 75 gallon, Ph - 6.8, nitrite - 0, ammonia - 0, Nitrate 20-40, GH 3d, KH <1d, total dissolved solids 300ppm, RO water conditioned with Kent RO right, <I'd use less, let the TDS hover around 100 ppm> Ph buffered with Kent Ph 6 and 7 (phosphates), and the temp is 25.5c. My 1st question is this- I read that the redness near the base of the fins could be Bacterial Hemorrhagic Septicemia. Does it sound like it to you? <This... is a condition... Need to seek out, address root cause/s... the trauma, "dirtiness" from the Colossoma... Takes time to heal...> 2nd, Can the pectoral and pelvic fins come back if I treat the fish correctly, or are they gone for good? <Can regenerate> 3rd, what/how would you recommend treating the condition(s) with and should the treatment be carried out in a separate tank, or is the condition contagious, requiring that the entire tank be treated. Many thanks! Scott S <I would try the change to foods with more bulk, lowering the TDS, soaking the food/s in a vitamin and HUFA mix like Selcon to boost this animal's immune system... Bob Fenner> Re: Bacterial Hemorrhagic Septicemia / fin and tail rot   6/30/07 Hi Bob, Thanks for the quick reply. <Welcome!> I'll take your advice and not medicate. How do I lower the TDS? <Mmm, either start with "cleaner" water or not add to it...> I add chemicals when I do water changes as follows. To 15 gal I add 1.5 tsp Kent RO Right, <Leave most of this out... this should do it> 1 tsp Kent Ph Precise 6.0, 0.5 tsp Ph Precise 7.0, and 15ml Tetra Black Water Extract. That brings my TDS in the new water to 235. Still even then my GH is very low, between 2-3 dH, and the KH is so low I cannot measure it. Would you add different quantities/products? Thanks again, SL <Try cutting back on the RO product... try a level teaspoon of baking soda (Sodium bicarbonate) instead...>
Re: Bacterial Hemorrhagic Septicemia / fin and tail rot, Silver dollar...  6/30/07
Hi Bob, You must have forgotten that I am using RO water, or I doubt that you would recommend that I only add 1 tsp of baking soda to 15 gal of it. <I did not forget anything...> On the label of the RO Right, it recommends 1 tsp per 10 gal for soft water. That is what I am currently adding. Also, on the Ph Precise I am following the label as well. Since my fish has out-lived my dog, I must be doing something right with respect to water chemistry and husbandry. <... what is your point?> My quandary is in treating an old fish which has lost much of its finnage, and over an 8 week period has not shown much improvement despite a great deal of effort. Your suggestion of more bulky food was a good one. The silver dollar seems to really like green beans, and since none of the other dollars pay any attention to them, the wounded one has them to herself and once again has a full belly. Also, I have taken your advice on supplementing vitamins. I have no experience with mixing food, so I am adding freshwater essentials to the water to add vitamins. Hope this works in lieu of. Thanks for your help, SL <Please... just use the indices, search tool. RMF>
Re: Bacterial Hemorrhagic Septicemia / fin and tail rot -- 07/01/07
Bob, <SSL> What is my point you ask? Most of what I do with respect to maintaining my fish tank is based on information gleaned from posts on your web site and from your direct responses to my previous questions over the past 2 years. I.e., RO water instead of tap, frequent water changes, softer water, discontinuing fish-slime additives, etc. <I am in agreement with all of this> Then, in this most recent volley of correspondence you suggest that I go to pure RO water without any additive other than baking soda <Sorry for the lack of clarity... I would try decreasing the RO Right product by half ml.s per time/maintenance interval, and in addition, add the level tsp. of bicarb> which would leave my tank with out any major or minor elements, no GH, and enough alkalinity to bring my Ph back up to 8.0. Why would you suggest this? It makes no sense to me in light of the other comments and suggestion on your site. SL <Do try this in a separate container... and measure the resultant chemistry... a day later. B>

Parasitized Metynnis - 06/27/07 Hello, Wet Ones! <In England, "Wet Ones" are moist towel things used to wipe babies' bottoms when changing their nappies (diapers). So, not normally something you call someone.> I have a silver dollar, Metynnis argenteus, that I think is parasitized. He was in quarantine (30 gal w/ air stones and Whisper III OTB filter) for 2 months, along with several rainbows, some hatchet fish, and some neon tetras. All appeared well in quarantine. We moved these fish to our 150 gal show tank about 4 weeks ago. After about 3 days we lost one of the hatchet fish to causes unknown. Four days ago we noticed a whitish spot on the side of the silver dollar and a similar one on one of the hatchets. The hatchet passed the next day. The silver dollar is still feeding well and swimming just fine! The white spot is diminished, but this dark spot just showed up. I've included three pictures. What is it!!! <Well, I can't see anything particularly worrying in the photo. Treating the tank with anti-Whitespot would probably be wise though, just in case. Hatchetfish are uncommonly sensitive fish, especially when recently imported. Once settled, they become a bit more robust, but the smaller species (Carnegiella spp.) never really become "hardy". Do bear in mind hatchets seem to need a lot of food to stay healthy, while silver dollars require at least some greens in their diet. Observing these two guidelines should help in the long term.> <Cheers, Neale>

hi. <Hello!> my oldest silver dollar has gone mad! - 6/7/07 <Oh dear.> he swims frantically around our tank & has hurt himself badly <Odd. Usually, this means the fish is unhappy for some reason. Can be water quality, but other factors to consider are: Noises (such as loud TVs or doors banging). Aggressive tankmates. Fin-nippers.> he has taken off his lips & fore head <Not sure what you mean by this. Is he damaged? If so, treat with anti-Finrot/anti-fungus medication to stop things becoming septic.> he does it at least twice a day <Try and establish if there is a routine. Are there children banging around the house when this happens? Characins are very sensitive to vibrations and sound. These are open water fish, and their response to alarm is to swim rapidly away from danger. In the confines of an aquarium, this can cause problems.> what's wrong with him? <No idea. Does he have friends of his own species? Silver dollars are very sociable, and won't really settled down if kept alone. A group of 6 or more is best.> our tank is huge & all checks are fine <Define "huge". At the very least, check there is plenty of swimming space and strong water current.> what do we do? <Not sure. How many silver dollars? What are the tankmates? How big is the aquarium?> thanks Donna <Cheers, Neale>
Re: silver dollar has gone mad! - 6/7/07
We have 3 silver dollars. His original friends died of old age. His new friends are only about 6 months old (had them about 3) but this behavior is new only about 2 weeks that he been acting weird, he took to the new babies straight away & hangs around with them all the time. <Very good.> Our tank is a huge corner one & we have a few female guppies & black & red shark & 2 Plecs. They have all lived happy for ages. The Water is clean, with filter & pump. He is about 7-9 years old & I have noticed him 'jump' before when I turned the Hoover on but in the past 2 weeks he has started dashing around our tank for no reason, he has hurt himself now. <Very odd indeed. He's a fair age though, so you've obviously been looking after him pretty well.> all the skin is missing from his lips & forehead. we are worried now & we don't know whether it is better to put him out of his misery. he's like one of the family though, we've had him years. <If he's otherwise fine, schooling with his pals and eating properly, then I personally wouldn't destroy him. I'd treat the tank with anti-Finrot/anti-fungus so that his skin heals properly. You could also add some Melafix as well. Give things a few weeks to see if he settles down. You might want to remove anything rough and spiky in the aquarium, just to make sure he can't damage himself further. You could also add some cheap floating plants, such as hornwort or Canadian pondweed, to see if the extra shade helps him settle down. A lot of fish enjoy floating plants. If things still don't improve in 3-4 weeks, then maybe then you might need to destroy him.> please help us thanks Donna <Cheers, Neale>

Silver Dollar Tetras   5/10/07 Hello was looking at your site under Characins, the two silver dollars, Myleus schomburgkii and M. rubripinnis are listed under other sites as reaching 39 cm long. Yours were juveniles then? < Probably close to adult size.> , anyway my question was the teeth. Do they bite your hand if you put it in the aquarium, do they attack other fish, harm them? < They usually attack plants. We use to call them plant piranhas. If they think that your hand is food then they will take a nip. This usually happens when people are trying to feed them by hand. The bites do no damage to the best of my recollection.> I know about the common smaller silver dollar M. hypsauchen do they also have sharp teeth but don't use them? I'm trying to figure out if I can put these larger silver dollars into a big aquarium with Tinfoils, balsa, one Oscar. < Silver dollars make a fine dither fish for med to large community tanks. Just remember that they love to eat plants and need some plant material in their diet.-Chuck>

Arowana and Silver dollars in a big planted tank, sys.  2/29/08 Hi, I have a question that has many different angles to be looked at. I have been reading your website for the past 2 or 3 years and have scoured about 50% of the freshwater info as I have found it invaluable. First off, I have a pretty big L shaped aquarium, 8 ft long, 45 degree angle of 4 feet, then another 45 degree angle of 8 feet with the tank being 2 feet deep and 2.5 feet tall acrylic tank (about 900 gallons +/- 50 from evaporation etc.). Ammonia and nitrites are of course zero, nitrates are between 20 and 40ppm (attributed to nitrate factory type trickle Bioball sump), pH at a steady 6.8 attributed to the large pieces of driftwood I have in their and their tannin releasing ways, hardness is at 80ppm. Temperature ranges from 74 to 76F in the mid to upper levels, 72-75F in the lower levels, due to lighting I guess. Filtration turns the tank over about 5-6 times an hour, though with cloggy filters, maybe only 3 times an hour. <Does sound like you need to upgrade the filtration a bit; in all honesty jumbo fish need all the turnover you can get. I'd be looking at 6x turnover minimum, and likely 8-10. If water quality is basically sound, you can perhaps get away with just adding a powerhead or two into the tank to keep the circulation of the water even.> It currently houses a foot long silver Arowana and a school of 11 silver dollars (the smaller 5-6" ones, not the red hooks). I also have 4 fairly young (only 1 foot tall, about 20 leaves) Amazon swords planted in 2 inches of gravel, and a whole bunch of Anacharis that's growing like a weed (for the silver dollars munching pleasures) though it is growing much faster than the fish are eating them. <Sounds great!> I also have some powerful full spectrum lighting across the two 8 foot lengths of the tank, nothing in the middle of the L. My more concerning question, or more likely, situation, is that my Arowana (I've had it since it was around 5") recently started taking dives at my silver dollars as they swim on their merry way beneath him. Is this a show of territoriality or is he trying to eat the silver dollars or both? <Either. Both. Arowanas are territorial and object to anything in "their" zone of operations. This varies with species, and Silver Arowanas are very much at the mild end compared with, say, Scleropages jardinei. But on the other hand that doesn't make them friendly community fish! If the Arowana is sufficiently big, it may be trying to eat them, or at least "sample" them to see if they're edible. A 6" Silver Dollar is borderline when it comes to safety with an adult Arowana. Some people have mixed them fine, I know; but look at how big the mouth of an Arowana can get! I wouldn't be 100% comfortable with this combo.> The silver dollars are way faster than him though so I have not yet scene what happens when he catches them. He is usually just silently sitting beneath a carpet of Anacharis during the day and only moves when fed (Hikari Arowana pellets plus weekly beef heart, plus whatever flakes, crumbles, bloodworms I feed the silver dollars) or when the lights are off. Also, I read that Arowanas generally leisurely patrol the aquarium all day and I figured now that I finally built my uber aquarium (oh that's right, self made... 20% of the retailers price... plus several cases of beer and pizza for friends who assisted in heavy lifting. <Ha!> Is it possible that my lights are too bright and the Arowana doesn't feel safe or its hurting his eyes, though he did just swim around normally for about a month until he started to "hide"? They are power compact fluorescents, 525 watts per light fixture, 4 total fixtures. This is a major concern to me as I have been keeping fish for the better part of a decade wanting an Arowana but refusing to get one until I could house it properly and now he just sits there. At night I have moonlighting and he does then move around quite a bit, this is why I suspect the lighting, but I never thought they were nocturnal... more diurnal from what I read. <Difficult to say on this one. Arowanas are noted for being photophobic, though most fish prefer shade to bright light. Do all the lights come on at the same time? Sometimes fish get alarmed by that, and having the lights come on across an hour makes a big difference. It does sound like he doesn't like the light. Is adding an understory of plastic plants (there are some great 3' plastic plants available now) an option? Something that could drape across the surface and cast some more shade? I suppose the experiment would be to unplug one light fixture for a day or two, and see if the Arowana prefers that end of the tank.> My next question has to do with the silver dollars and them seeming to enjoy eating the Amazon swords more so than the Anacharis. Is there some other large show plant that does well under high lighting that the silver dollars wont want to eat? <I'd perhaps look at Crinum spp., e.g., C. calamistratum, as these do seem to be left alone by herbivores. They're big and generally hardy. Java fern will do great under bright light, though it does tend to become an algae magnet. Anubias even more so.> Also, my swords aren't exactly growing as well as they had in past tanks with 4-5 inches of gravel. Does the gravel depth make that much of a difference? <Yes; also the quality/composition of the substrate.> I have something like a thousand Malaysian trumpet snails aerating the gravel and what not but am concerned that if I add more, the snails just wont be able to irrigate and aerate all that gravel, and the last thing I want is some anaerobic environment unreachable by plant roots or snail burrowing releasing poisonous hydrogen sulfide and the likes into my tank, plus stinking up my fish room. <Just doesn't happen. The "anaerobic decay" thing is largely a myth. Happens naturally in ponds and in marine tanks (inside living rock) and no-one fusses. So by all means ramp up the depth of substrate to what worked before. Do also check first that the substrate is adequate though -- Amazon swords want a nice rich soil or Laterite enriched substrate, and plain washed gravel just won't work for them.> Should I consider ditching the silver dollars for a school of tinfoil barbs? They don't eat plants at all do they? <Tinfoil Barbs can, will eat plants.> And lastly, as you may have guessed it, I want to add more fish to this tank as it seems fairly empty... I'm thinking black ghost knife? <In theory fine, but you'll be hard pressed finding an adult large enough for this community. Mostly you only see baby Apteronotus for sale.> I first filled up the tank about 8 months ago, filling it with something like 100 Malaysian trumpet snails and about 20 mystery snails for my tank cycling. I over fed the snails for 3 months in order to obtain the current population explosion of snails I now have, <Consider adding a group of Clown Loaches or thorny catfishes (Doradidae). These will eat the snails, if sufficiently hungry.> at the end of month one I added the sword plants, then I added the silver dollars at the end of month 3, all at about the size of, well, silver dollars. They mostly hid in the center decor castles of my tank for the first two weeks but then began to sprint (if you will) from one end of the tank to the center and back (they seemed to never travel into the leftward portion). After having them in there for 2 months, they had grown to about 3" in diameter each and I added my Arowana at 5". After only another 3 months the Arowana (from what I could tell) doubled in size, which I attributed to it having so much space to swim. <Or simply good maintenance. Arowanas grow quickly if kept well.> Now I added the Anacharis about 2 weeks after the Arowana was added and it was generally ignored by all but a couple of snails. Then a month ago (beginning of month 7) is when the Arowana began to just sit under the Anacharis. So yeah, back to the black ghost knife... I want to buy two of these guys (I figure the tanks big enough) and I put two PVC condos with 15 pipes of 2" diameter and 1' length in there, one in each 8' portion. Should I be concerned about the Arowana eating them as I often find the knife fish around 4-5 inches in length max, and it will be some time before they grow to their 2' potential where the Arowana wont (hopefully) eat them. Are the black ghosts fast enough to evade the Arowana if pursued? <No; sooner or later, if they're small enough to swallow, they'll be eaten. The Arowana only has to get lucky once!> And for the record, despite clown knives growing huge and not being swallowable by my Arowana, they will probably eat my silver dollars and knock over my plants, and just grow too big for my taste, so that options out. <I agree.> Well, that's all for now. I literally read all over the web for months and abstained from just writing you guys since I know how annoying it can be to be asked simple questions that have their answers everywhere... but I just cannot find anything like this Arowana diving at silver dollars thing while not swimming anywhere else. I am a student of the sciences, my job being that of a biochemist, therefore I was cocky, stubborn, and reluctant to ask for help (a character flaw repeatedly pointed out by many over the years)... but there are just some things you cannot learn in books. I'll likely have another question or comment in a couple of months after the knife fish are added... if they are compatible. Thanks in advance for any advice you can provide. With Best Regards, Matt <Hope this helps, Neale.>

Re: Arowana and Silver dollars in a big planted tank (RMF, please comment)  2/29/08 Well It looks like I'm going to be upgrading my sump pumps using some pond pumps to get that water flowing up to the 10 times over level. I currently have four overflow filters going into four 55 gallon tanks... I guess I will just have 4 extra pumps to sell on aquabid.com as I replace them with the pond pumps. The pumps I have looked at are reporting 1800 gallons an hour (Danner Supreme Mag Drive Aquatic pumps, I currently own the 1200 gph pumps)... am I going to need larger sumps or will this push through the 55 gallon tanks just fine? <No idea; RMF, any thoughts?><<I would definitely be reading, making careful choices here... There is much to be saved in the way of electrical cost, pump noise, waste heat, service life, by making good decisions re pumps... The Sequence series/Baldor motored lines are some faves for the size, application here. Other fractional horsepower pumps are ably reviewed here on WWM: http://wetwebmedia.com/pumpselmar.htm and the linked files above. RMF>> This company also sells a 5000, specifically designed for large ponds and waterfall displays which reports 5000 an hour. Is that overkill or should I add one or two of those in too? I guess two 1800 and two 5000 gives me 13600 gallons an hour claiming about 15 times an hour for the whole tank... realistically maybe 11-12 times an hour turnover? <Probably overkill. 8-10 times turnover should be adequate.> As for the silver dollars not being fully compatible, I will look into giving them a new home. I have just been keeping silver dollars for 7 years now and figured I was pretty good at it. My last batch of 7 didn't die, with the oldest being 5 years old starting in a 55 gallon and moving up to a 120 gallon for the remainder. I just gave them to the LFS before I moved halfway across the country for the job that would allow me to have such a lavish aquarium. What other fish come to mind, that would be an attractive school of 15-20, that could be raised in one 8 foot section (separated by a divider) until large enough to not be eaten by the Arowana? I'm thinking Bala sharks? <A good choice. But also Semaprochilodus taeniourus look amazing in large groups, and are nice Amazonian fish.> I read they get to 12-15" and from my limited experience, are very fast. <Oh yes.> Do they eat plants because I cannot find info saying that they do, but then again, I was wrong about the tinfoil barbs. <Balantiocheilos melanopterus generally ignores plants. It eats green algae and invertebrates, and may nibble on tender shoots, but that's about it.> Maybe 6 months separated, grown to 7-8 inches then set to survive with the Arowana? <You may also be able to get adults via Fish Forums, fish clubs, etc. Lots of people buy them, and then have to rehome them when they get too big.> Are their any other fish you could recommend as I have limited experience with large schooling fish. <There are a lot of nice big barbs. Severums would also look quite nice, and occupy the midwater. They're territorial when spawning, but your tank is big enough that shouldn't be a problem. What about catfish? Sorubim lima is a nice big (45 cm/18") schooling catfish. It's very peaceful, pretty, and quite easy to obtain. It famously likes to swim vertically leaning against plants and rocks, so is definitely fun.> As for the lighting, the timer IS set to go on all at once come 10am and turn off at 8pm. Some sunlight does come through the one window and glass door to wake the fish up, but I guess that is nothing compared to a full 2000+ watts blazing into their eyes all at once. I can turn on the actinics at 10 am, then 2 of the other full spectrums on at 11, and the rest at 12... and then shut them off in the same manner (off to Home depot again for more electric timers). I assume this will still be ample light for the Anacharis and Amazon swords. <Should be. Try it, and see what happens!> And I do have two 3 foot plastic plants draping across the top of my tank which cover an area of maybe 4-5 square feet each. They are located in between the Amazon swords as to not rob them of light. I don't really want to put much more over the plants, but there are still many other places in the tank to add another 4 to 5 of those 3 footers without disrupting light to the live plants. I will give them a try since they are cheap and fairly realistic looking. As for the other plants, I do have an Anubias growing on a piece of driftwood, though the plant is 3 years old, started as 3 leaves, has maybe 30 now, and has only moved about 1 foot across the driftwood (3 foot long driftwood). It used to be house with a Pleco so perhaps his constant sucking of the driftwood would constantly cull the Anubias... or maybe the thick film of algae growing on its leaves is inhibiting it? <I've tried Anubias with my Panaque, and it gets turned into a Swiss Cheese Plant, so I agree with you here!> Ill try out the C. calamistratum when I find it. If nothing else the LFS can order it for me. <Mail order plant distributors abound, and this is a fairly common species, at least here in the UK.> I do have a Sailfin Pleco in there too. He's only about 8 inches long though so he is having a problems stopping all the algae as of yet, though I have faith in him (or her, I cant tell yet). <Once they mature they aren't really algae eaters, so don't hold too much store by this. Plecs generally are omnivores, and algae is only a part of their diet.> As for my substrate, it is just painted black artificial gravel. I add trace minerals for the plants, but I guess that's just not gonna cut it. <Indeed.> It will take some time to clean all 200+ lbs of gravel out, but I would say in half a years time I should have 4 inches of Laterite enriched substrate in there. <Can't begin to tell you how much I sympathise! Anyone who has grown aquarium plants (or tried, at least) will have been through the mill of changing substrates.> I guess I wont be getting the black ghost knife anytime soon, if ever, aw well. <Again, look out for "second hand" specimens.> Maybe I'll get some water in my 120 and raise him in there until he's big enough for the show tank. <Quite.> And perhaps I misspoke about the snails as a pest, as I want them in their. I have never been able to keep a tank as clean as I do when I have snails in their. <I wonder if Apple Snails would help on the algae front?> I once had a tank with 4 yoyo Loaches in there that cleaned out the snail population, there was a gradual decline in water quality, and an increase in detritus and algae that I fought for a year... I removed the loaches to the LFS and my tank recovered to crystal clarity in 3 months time. <Not impossible.> Therefore, largely based on this single experience ( I know, that's poor scientific form) I like to always have snails. And despite the appearance of (now about 100 mystery snails) snails crawling all over my tank with about 1 snail on every 4 square feet of glass (or I guess acrylic), I find it more peaceful and artful than an eyesore. <Indeed.> It looks to me as though your experience in the trade has done it again. Thank you very much for your assistance. Matt <Good luck, Neale.>

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: