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FAQs on Silver Dollars

Related FAQs: Serrasalmine Fishes, Piranhas, Pacus,

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.
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 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 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>

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>

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, 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 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 - 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 Genius 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


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. Thy 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


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.

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.

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.>
Branon
<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 jardini. 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... Im 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.

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 Im 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? Im thinking Bala sharks?
<A good choice. But also Semaprochilodus taeniurus 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 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.>

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