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FAQs on the Piranhas Disease

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

Related FAQs:  Piranhas 1, Piranhas 2, & FAQs on: Piranha Identification, Piranha Behavior, Piranha Compatibility, Piranha Selection, Piranha Systems, Piranha Feeding, Piranha Reproduction, & Piranhas and Relatives, Feeding "Feeder" Goldfish, Pacus, Silver Dollars,

Very sick piranha -- URGENT!!!. 7 megs of pix, no rdg. Using WWM    4/18/16
Hi.. We need help, please. We've had our piranha for two and a half years now. She's a beautiful red belly.
<... not solitary species. Had you read...>
We made the mistake of feeding her feeder fish (I didn't know how bad they were)

and now for the past week he has just been getting worse. I've been putting MelaFix and sometimes PimaFix
<Worthless; worse than. READ>

in the tank with her. We're going to test our water tonight and do a water change. I am beyond worried.
Her fins are rotting, eye cloudiness and sores all over her body. She just sits at the bottom and barley moves.
How can we fix this?? Please help.
<Maybe a blitzkrieg treatment for worms and Protozoans... Praziquantel and Metronidazole. READ here:
and the linked files above, AND the two compounds mentioned. Bob Fenner>

re: Very sick piranha -- URGENT!!!.... Using WWM
Do you think if I clean the whole tank it'll help?
<? Is there some compelling reason to do so?>
I've never even heard of these types of fish meds and I worked in the pet store in my area..
<Then don't write. READ
. BobF>
re: Very sick piranha -- URGENT!!!

I'm sorry but I'm confused on your answer.. Of course there is a good reason to clean her tank.. She's sick.. I'm no fish expert but I would think that a water change would help a little.
<Nope...><<Had this person read.... IS the water appropriate now? Soft, acidic, tropical... with little metabolite?>>
I'm sorry that I've never heard of these meds.. I'm looking for help and that last e-mail from you was very rude.
<Go elsewhere if you won't read>
re: Very sick piranha -- URGENT!!!

There's no need to be rude. I'm sorry I'm very worked up over her being sick. I am reading your information I just haven't had a chance to read the whole link as I am working.
<<Though time to write nonsense>>

MY PIRANAH, env. stress/disease; full moon?     10/27/15
STOP SHOUTING! Please re-key and re-send your msg., not in all-caps. B
MY PIRANAH. Env.      10/27/15

Due to a power outage last Friday, I had no power in my home from Friday till today, Monday............The temperature in the house went down to 61 degrees.....................
My snakes luckily survived, as did my red belly piranha. The temperature in his tank went down to 62 degrees for a day and a half, but now it's back up to 80 degrees. I allowed the temperature to slowly climb back to 80 degrees and changed 25% of the water. The piranha is swimming upside down and on his side. any suggestions?
<Really just time going by.... I would have only raised the temp. to the low seventies for a few days.... Too much, too fast and enzyme systems collapse, can't keep up. Bob Fenner>
Thank you,
Robert Berlin
Re: MY PIRANAH     10/27/15

Will antibiotics help??
<Help what? No. BobF>

Piranha Health, Feeding, Behaviour - 10/18/2012
Hi, my name is John and I have a red belly piranha and I was reading and noticed it was a really bad idea to put feeder fish in there so I'm going to take them out.
<Very good move.  He will do much, much better eating meaty prepared dry and frozen foods.>
But I was wondering if it was too late for my fish friend. He is acting weird, he keeps swimming into my glass and stays on it for awhile looks like he is chasing himself or kissing it.
<This could just be normal behaviour, chasing/biting his reflection.... 
Without clear details about your tank (size, water quality, etc.), it's hard for us to know from a distance.>
He also will swim sideways and rub his side on the gravel.  Not sure why he does this.
<This could be bad news.  Test your water for Ammonia, Nitrite, Nitrate, and pH.  Ammonia and Nitrite must be ZERO, and Nitrate less than 20ppm.  If there is any Ammonia or Nitrite at all, or Nitrate is higher than 20ppm, do water changes to correct the problem.  If you can't test your water right away, then do a nice big water change anyway, just make sure that you dechlorinate, and try to match temperature and pH.  Piranha are pretty resilient, but do prefer soft water with a slightly lower than neutral pH if possible.>
Just trying to figure out why he does this all day then sits under my filter for a couple hours then he'll be at it again.
<As above, check your tank's water - or if you don't have test kits, ask your local fish store to test it for you and to show you the results.  As to why he just sits around under your filter, make sure your tank is suitably large for this very big, active species.  Also bear in mind that, although piranha are very aggressive, they are a schooling fish.  Without more of his own species to hang out with (and a VERY large tank to house him and his buddies), he's not going to act normally.  The flashing (turning on his side and scraping on the gravel) is disconcerting though, and suggests either a water quality problem or possibly a parasite or other problem brought in with the feeder fish.  Watch him closely for any abnormalities, especially signs of "Ick" (Ichthyophthirius multifiliis), a parasite which will show up as little white specks on the fish, and is often brought in by feeder fish.  Also, keep reading, on WWM and elsewhere, about piranha care, behavior, and disease.  Your pet is sure to thank you for informing yourself about him, and you'll enjoy learning more about this wonderful, toothy Serrasalminid.  Wishing you and your fishy pal well, 
Tyvm really appreciate it
<Glad to help.  Do keep reading, learning, and enjoying your fish. 

Piranha Injuries    1/14/12
I put some new Red-belly Piranhas in with my old one recently. The original one started to nip at the others.
<Absolutely typical and predictable.
The "schooling" behaviour of Piranhas is much overstated, misunderstood.>
He has stopped now, but the other piranhas are looking pretty bad. It looks like there is a lot of dead skin/scar tissue on them.
Can you tell me what the healing process is like and whether this looks normal?
<In good conditions, Piranhas heal astonishingly quickly. Wild specimens will bite one another quite severely at times, yet this seems to do relatively little long-term harm. On the other hand, aquarium conditions are rarely as good as those in the wild. Let's assume some basics here: You must have at least 6 specimens of Red-Bellied Piranha (Pygocentrus nattereri) for them to have any chance of schooling together. In smaller groups the dominant one will eventually kill the others. So, you have 6 specimens, at least, at least, and therefore an aquarium upwards of 200 US gallons; anything smaller isn't going to work either, partly because of the size and behaviour of the fish, but also because of the need for low nitrate levels and high oxygen levels. So, assuming your 6 specimens in 200+ gallons, you will probably find they'll heal under their own steam.
Piranhas are a bit sensitive, so I'd tend to steer away from formalin, copper and organic dye medications. Melafix might be okay, if you wanted to use it, and antibiotics shouldn't do any harm. But I'd wait to see if the damaged specimens were healing on their own first, and only medicate if the wounds weren't cleaning up. Obviously in an aquarium smaller than 200 gallons things get more hostile, both in terms of persistent aggression and poor water quality, and you may need to think carefully about medicating promptly, use of a hospital tank, and ultimately rehoming.>
Thank you!
<Cheers, Neale.>

White spot on Piranha  12/28/10
Hello. I'll warn you right now that I'm the type of person you HATE to hear from...
I have a piranha and have no clue how to take care of it.
<Mmm, well... as you likely are aware, the several species of Piranha are extremely social animals. Live in shoals... not singly, where they more than tend to be very skittish, dash themselves about in their systems,
traumatized, short-lived...>
A buddy of mine had an ~8inch red belly, and a ~12inch Pleco. He got shipped overseas to serve in the army, and said if I didn't take them he'd just throw them out.
Luckily I have a heart, so I took the fish. They are in a 20 gallon tank
and can hardly move (yes, I know, he should have never had these fish in the first place) and I have no idea what to feed them or how to take care of their water.
<Not to worry. Help is available. Please start by reading here:
and the linked "Piranha" FAQs above>
I'll be buying a 50 gallon tank in the next month, and I picked up a water testing kit today which I plan to use when I get home from work. I noticed the piranha has a white circular m&m sized spot on it's side. I have no idea if that has always been there, but is there some type of medicine I should be putting in the tank to clear it up?
<No medicine. This mark is most likely from a physical accident... perhaps compounded w/ declining/poor water quality. Be careful re feeding this fish (it won't starve) for now... Move all water and gravel, decor from the existing tank into the new 50...>
I bought algae disks for the Pleco, and cichlid pellets and freeze-dried shrimp for the piranha.
<Won't likely eat these>
I guess I'm just looking for some reassurance that I'm doing this right, and wondering if there is anything more I should be doing right now.
They really are beautiful fish, and I've completely fallen in love. I want to make them as comfortable as possible. Thank you so much for all your help!
<You are embarking on an adventure that will grant you great insight and enjoyment throughout your life. I/we will help you on this journey. Do write back if/when you have specific questions. For now, read where you've been referred to. Bob Fenner>

Spots on Piranha; no real data; RMF, any ideas? <<Yes; env. easily... poor water quality>>   11/18/10
Hi I have six red belly for about 7 Months in 100 gallon , I recently noticed they are getting darker, but strange thing is that they started having dark spots and I was wondering if its ammonia burn or sometimes
<Hello. Several piranhas naturally have spots, including Serrasalmus maculatus and Serrasalmus marginatus. So it's worth checking what you have against pictures of these. Pygocentrus nattereri has spots when young, but these are normally lost as the fish mature. Ammonia burns are usually distinct from normal spots. They're usually brownish blotches, irregularly scattered about, and unlike spotted markings, asymmetrical when the two sides of the fish are compared. There are some parasites that can cause black spots, including Black Spot Disease, usually seen on pond fish. If you were silly enough to use live feeder fish, I suppose it's possible that you've introduced these parasites. But I hope you've read enough about
piranhas to know that feeder fish are not only parasite bombs but also far too rich in fat and thiaminase to be fed to piranhas. Fat and thiaminase cause nutritional problems, including neurological ones, and nerve damage can cause fish to display the wrong colours. The correct diet is, as I hope you know, a mix of thiaminase-free fish and seafood meats such as tilapia fillet and smelt, together with things like earthworms, krill, and occasional plant foods including seeds and cooked peas. One of the most common problems with diagnosing predatory fish is removing the "feeder fish factor" -- if someone was foolish enough to use store-bought feeders or any type of thiaminase/fat-rich feeder like goldfish or minnows, all bets are off! It's virtually impossible to tick off the potential problems caused by feeders. Thankfully, feeder fish are virtually absent from the UK trade, but in some parts of the world they're still sold. Shame really. Anyway,
hope this helps. Cheers, Neale.>

Sick red bellies    9/13/10
Hello I have a Red Belly in a tank with 6 others, (120 G) and just recently he formed a long stringy feces coming from him,
<Can happen simply as a result of diet, but Hexamita infections also cause these symptoms.>
he is still eating very well and the others are not picking on him, I do feed them deer meat with a garlic extract and keep the tank at about 24.
<I wouldn't feed this fish deer meat. Any particular reason for choosing this? Let's recap: the basic diet of Red Bellied Piranhas in the wild is fish, invertebrates, fruits, and seeds. Mammal meat is an occasional "treat" rather than a staple, despite what Hollywood might suggest. I find it ironic that many piranha-keepers become obsessive about feeding their piranhas mammal meat in completely non-natural amounts, while totally ignoring the fact their piranhas also eat fruits and seeds! Reveals the lie in all this nonsense about giving them feeder goldfish "because it's what happens in the wild"; if they wanted to keep their piranhas naturally, why aren't they offering fruits and seeds? Anyway, my point here is that if your piranha is producing unusual faeces, there's a good chance it's diet
isn't right. Obviously you should never, ever use feeder fish unless bred at home, and even then, never cyprinids (Goldfish, Minnows, etc) and only ever livebearers, killifish or cichlids. If you've ever used feeder fish from the store, then all bets are off, and frankly, there's a good chance you've infected your piranha with something difficult to diagnose and/or incurable. Over here in England feeder goldfish aren't even available, so it's a non-issue, but our friends in the United States still persist with this idiotic and dangerous practise. Next up, reduce the amounts of mammal and bird meat. Warm-blooded animals contain oils that fish have difficulty digesting. In the cold bodies of fish there's a risk those oils congeal inside the gut or elsewhere. Instead concentrate on thiaminase-free fish, for example tilapia. Whole, unshelled shrimp is also useful as a source of indigestible material that helps to clear blockages from the gut, but shrimp contains thiaminase and has to be used in moderation. In terms of
vegetable foods, cooked peas are excellent if your piranhas will take them.
Otherwise some success has been had offering things like sunflower seeds and pumpkin seeds to piranhas. They may need to be motivated by a few days of starvation, but rest assured, such foods are a natural, perhaps
essential, part of their diet. Obviously if you can get your fish onto pellet foods, then such foods generally provide a nutritious staple around which other fresh and plant-based foods can be added.>
the water is changed every 3 to 4 days, about 10 to 20 %, all my levels are great and other than this there seems to be no problems is it a parasite.
I can not find anything reliable online, and my local pet stores are not sure what to treat for, one says parasites the next says something else.<Doesn't sound like a parasitic infection just yet. Would keep an open mind for now.>
Could you help I really enjoy my little buddies.
Thanks Travis
<Hope this helps. Cheers, Neale.>

Possible large burn on our new Piranha -- 03/03/09 just after reading every tidbit of the FAQ on Piranha on this wonderful site I finally found by accident (lol) I thought I might see if you can answer 2 questions about this newest member of my home. It is about 4.5" long now and was rescued by our friendly pet store owner before the previous owner flushed him down the pipe! Somehow, during one capture "apparently" he sustained either a large burn (possibly from the heater???) or the guy damaged his side after being bit..... we are not totally sure.. I have a picture to send to you of the wound, maybe you can tell us the best treatment for this and Googling "tropical fish first aid treatment" and multiple variations of the same comes up with anything but an answer. the second part of the question is if this could possibly be a Gold Spilopleura possibly, or if it is not then maybe you could possibly shed some light on what variety he is for us.. many thanks in advance for your time :) Ron <Ron, since Piranhas by their very nature get injured all the time, I'd expect this fish to heal quickly. I would treat with a suitable antibiotic or antibacterial (not Melafix or salt!) just to keep the wound nice and clean. But given time and good water, I'd expect he'll be right as rain in no time. The wound itself could be burn, or an ulcer following some type of physical injury. Almost doesn't matter now, so I'd not fuss unduly provided you're comfortable his new home is safe. As for identifying the species, I'm not a world expert of Piranhas by any means, so would encourage you to get a second opinion from one of the Piranha-specific forums. But I suspect this is Serrasalmus gibbus or something similar. I don't think it's Serrasalmus spilopleura. There are a bunch of unnamed varieties in the trade, usually sold as Serrasalmus sp "trade name" or some such, for example Serrasalmus sp. "Black Guyana". Keeping on top of all these varieties is hard work, and I'm afraid I don't have that expertise! It is a Serrasalmus though, and that means it will be fairly big, solitary, and somewhat difficult to maintain without ensuring good water quality. As is usual with Piranhas, take care to feed sparingly and using healthy foods: no feeder fish! Your specimen has an open wound, and the worst thing you could do would be to dump some "parasite bomb" feeder goldfish in there! Concentrate on earthworms, river shrimps, squid, etc. Fruit and seeds are a significant part of their diet too. Cheers, Neale.>

Piranha problem? Hey what's Up! I would appreciate it if you could write back to me as soon as possible just bought 8 piranha for my tank. They are all babies a little bit bigger than a quarter. Anyway I went away for two days and my heater went crazy, I came back and the water was at 90 degrees. I bought a new heater now. I did a water change, added new water and added plenty of stress coat. My fish look like they are back to normal! Two of my fish fins are really damaged they Dorsal fin, it looks like they have been stripped down or eaten. <Very likely have been chewed by the other Piranha... very common. Not the heater; many species (there are dozens) do live in water in the mid to upper 80's seasonally.> Could their fins be prepared? <Yes. They can/do regrow in time. Just need to keep the whole lot fed (a few times daily), provide enough hiding spaces (plants, driftwood...) and keep up your water quality> Their eyes look cloudy. If these two piranhas died could I add two new piranha similar size to my tank. <If the system is large enough. You need a good two hundred gallons plus for this many of the smaller size species of Piranha. Please see here: http://www.wetwebmedia.com/FWSubWebIndex/serrasalminae1.htm> I have had my piranha for two weeks. I know once the tank is established you cant added a new piranha but since they are young could I added them???? Thanks A lot Barry <I would definitely not add any more unless your system is as large as stated. Bob Fenner>

Piranhas Hi my name is Katie...I have a couple of questions thank you by the way your website has already answered some of my questions! I have a 55 gal tank, if I got them a 100gal to 150 gal tank will they get bigger, I have a one female and she's big but all my males aren't very big at all I have 5 all together) >>A bigger tank is always better. You will have a hard time with water quality in a 55g. Do you know your ammonia, nitrite, and nitrate levels?<< My 2nd question is one will get eye cloud and then the rest will get it all they are eating right now is freshwater shrimp could that be a problem? >>Yes. You need to treat them with a broad-spectrum antibiotic. Again, what do your nitrates measure?<< I only have one filtration system in there could that also the problem should I add some more I've had them for almost a year now so that would make them almost 2yrs old and it's been the same filtration system... >>How often do you do partial water changes and clean the filter?<< They also get really pale during the day and night for about an hour there bellies are really red and then they get really dull. I just want to make sure I'm doing everything o.k. love them and wouldn't want anything to happen to them. well I appreciate it if you could reply to this when you guys have sometime. thanks Katie:) >>You are welcome. -Gwen<<

My Piranhas (Sung to the tune of "My Sharona!") <Hi Katie, I'm not the one that answered your previous email, but I'll assist you with your piranha problems.> I do treat them with an antibiotic but it seems like every time we do that there fine and then it comes back even worse and then it starts with two and then all of them... <Then this is a sign that the tank itself needs work, not just the fish.> my boyfriend checked the ammonia level the other day and it was fine we can't seem to maintain pH.. <I don't know the size of the tank you have the piranhas in but these are rather messy fish and need lots of tank space. Piranha have evolved from fin-nipping species of fish. Their ancestors were small little fish that actually survived by eating the fins of larger fish. And through evolution they evolved into the larger voracious Piranha breeds you see today. That means that these fish will nip at each other if not given enough room. And when fish are left in an environment when their tankmates nip at them their health quickly deteriorates leaving them vulnerable to many different types of parasites and sickness. Aside from needing a large space, the major concern with any piranha owner is that these fish need some of the best filtration that can be offered to them. I had raised friends piranha for a while, when they were away at college and during that time I realized that only the best filtration should be given these fish. I doubled the filtration of the tank to help with seemingly endless illnesses... I found that the increased water flow and cleaner water made a great deal of difference. As for that, I would also suggest you set up a quarantine tank if you don't already have one. When I fish becomes sick remove it from the display tank and move it to a separate tank. This removes the chances of the problems spreading to the other tankmates. Also a sick piranha is more likely to be picked at by others, which isn't fair to the sick fish.> also what does that mean when they float near the top or they float kinda sideways not completely only a little bit and it doesn't happen all the time. <When fish that don't normally float near the top are seen there, that typically is a sign that their isn't enough oxygen in the water for the fish. Oxygen levels are higher at the surface of the water where oxygen exchange happens. This is a sign that you are not offering the right environment for these fish. You will need to bump up the filtration on these fish, and offer powerheads, and airstones/pumps to help with surface agitation to help increase the oxygen exchange. I feel that the reason these fish are getting sick is that the water quality is not up to the standards it needs to be. I suggest you check out some of the piranha forums online and talk to the owners. You will no doubt learn a great deal of info from them. A few places to start out with iswww.aquatiqterrors.com or www.piranhafury.com. Both of these forums offer knowledgeable crew members specializing in piranhas.> thanks again Katie:) <Good luck with the fish, and hope they do get better. -Magnus>

Piranha Problems I have had a 29 gallon tank with 2 red belly piranhas in it for about 2 and a half years now.  There are 2 filters, one just the regular whisper filter and the other is a biological filter. One piranha is much bigger than the other one and always has been because it gets to more of the food before the smaller one.  About 2 weeks ago, I noticed the smaller one looked very malnutritioned and it would not eat.   <It does sound like he was outcompeted for food.> My piranhas have been on a regular diet of beef heart for the most part since I have had them.   <Beef heart is not an ideal food for any aquarium fish.  The highly saturated fats in this and other mammal and poultry meats are indigestible by fish and will accumulate in the liver, possibly causing serious health concerns down the road.  Please consider using fish meats, like fresh salmon or trout (preferably boneless!), cut it into manageable pieces and freeze before feeding it to them.  You could use prawns, cocktail shrimp, prepared meaty fish foods (I like Ocean Nutrition's "Formula 1"), or prepare your own frozen blend of such foods.  Here's a link to a basic plan of how to make your own foods (the article is reef-oriented, but will serve well to steer you in the right direction in feeding any tank, just adjust to that tank's needs):  http://www.ozreef.org/diy/reef_food.html .> The small piranha was unresponsive when I would put my hand near the tank, and that would normally make it swim away.  He had no physical signs of sickness other than looking very thin. I did around a 40% water change about 10 days ago.  The water change did not help and to get straight to the point, the small piranha died tonight.   <It could very well have been that he was outcompeted for food by the other piranha, and simply starved, or it could have been internal parasites, reaction to water conditions, etc.  Too many variables to tell for certain.> Now throughout this entire time, my bigger piranha has seemed very healthy and has been eating consistently.  However, when I found the small piranha dead, I noticed that the bigger one was acting a bit lethargic.   <Ooh, not good to hear....> I just did a 50% water change, and my water is fine, <That's rather vague, can you tell us specific water parameters, especially ammonia, nitrite, nitrate, and pH?> but I am very worried because my only piranha is darting back and forth, and swimming to the top of the tank.  He seems to be breathing fast too.   <Yikes, this sounds like a reaction to something in the water - did you dechlorinate the new water?  Did you match temperature and pH?  Again, water parameters will help determine what is going on.> The only other option that I know of is to medicate the tank with Oxytetracycline.  Should I use it?   <I would not, not without knowing what you need to treat for, if anything.  Again, it sounds more like shock from something in the water from the water change.  My first guess would be chlorine poisoning, which is why I ask if you dechlorinated - and are you sure you used the right amount, if you did?  When you refilled the tank, is it possible you used a receptacle that had held any household cleaners?  Have any possibly toxic foreign objects made their way into the tank?  Is all equipment functioning properly?> What should I do next?   <If you did not dechlorinate the water, I would do another major water change, replace with dechlorinated water of the same temperature and pH.  If you *did* dechlorinate, then we'll be back at the drawing board, hopefully after you let us know your water parameters.  It does clearly sound like he's irritated from something in the water.> I could definitely use your advice because I don't want to lose my last piranha.  Thank you very much in advance.  ~Jeff~ <I do hope we can help you out, Jeff.  Please get back to us, and keep us updated.  Wishing you well,  -Sabrina>

Piranha tail injury I purchased 2 gold (Spilo) piranhas from a fish store. <This is Serrasalmus spilopleura, yes?  I'm used to these being called red-bellied piranha, so I don't know if we're thinking of the same fish> I did a little research on them, but after I got them I did some more and realized it was a bad  idea having two in the same tank. Sure enough, after about 3 weeks in my 55 gallon the meaner of the 2 (always charging the tank when I came around where as the other would hide) bit my other one in half. <Yeowch!  What a way to go!  I guess I need not say that it's always better to do all your research before getting the fish....> When I first purchased him, he was in a tank with about 30 others so fins and stuff were bit off. I've had him for about two months now (he's about 3 inches) all the fins grew back except for the bottom half of his tail. It looks like it was bit off at the end of his back bone, and I wanted to know if the bone just takes longer to heal than fins or will it never grow back? <Well, since the damage was so extensive, and it's had ample time to heal, it may simply be that way the rest of his life.  Give it some more time, though, and just keep an eye on it.  Consider it a battle trophy, not a flaw ;) > Since he's now in a tank all by himself except for a Pleco he doesn't bother with, <Lucky Plec!  Though seriously, the Pleco's probably perfectly safe, as long as the piranha's fed - as you've already observed him to be.> I want him to be 100%. Also I was wondering how large my piranha will get in my 55 gallon. <Well, FishBase.com says S. spilopleura gets up to 21cm (about 8.5 inches), and I daresay I've never seen this species grow larger than that, so he'll probably be fine in the 55, if he and the Plec are the only inhabitants. Please write back. Thank you <You're welcome. -Sabrina> Ken R.     

Piranha with gill curl I know Arowanas get this. I have bought a rare piranha. (Pygocentrus piraya) And it has gill curl. I know it is not from me. The fish was 2 inches in size when I gotten him, So I did not notice the gill curl in time. It is pretty advanced now being that 1/3rd of the hard part is affected. What surgical procedure do you recommend? If I cut all of it off it will show a good deal of his gills. Or do I make relief cuts in the gill toward the head? Or a little of both? <Actually, neither of these. I would leave this animal as is. "Gill curling" is almost always either a manifestation of genetic disposition or a developmental anomaly. The last due to "poor water conditions", lack of dissolved oxygen, nutritional deficiency... Not "correctable", and likely more dangerous to cut the existing structure in hopes that it will regenerate "properly" than the possibility of damaging, killing the specimen> As him being a piranha. A feisty one at that. What tranqs are easy for a hobbyist to obtain? <tranqs?> I have never done any surgery. So if you could give me a step by step instructions that would be great. Thank you very much. <Bob Fenner who would "live" with the curled gill cover.>

Recurring Piranha Fungus... something/s missing in set-up, care Good morning, <And to you> We have a 30 gallon tank with rocks, a filter, a heater, and a red belly piranha. We originally had two fish, but a nasty bout of fungus killed one of them. <Unusual... if your water is suitable at all... mid to low pH, not too hard, heated, cycled, filtered... Piranhas are by and large tough, disease-resistant> Since then, the survivor fish (Ali) is on his third bout of fungus in two years. I keep Maracyn-Two and Maroxy at home. Two days ago, Ali's had a patch on his eye and a tuft of fungus near his fin. The fish store once told me that adding some marine salt helps so I added one tablespoon two days in a row. Yesterday he was really slowing down, so I medicated with Maracyn-Two, because his symptoms most resembled the description on that box. This morning he has fin rot, which seems more like the Maroxy symptoms. Which medicine should I use? <Ideally none> Can I switch now that I started with the Maracyn? How can I help prevent this? <Let's review your system... Have you read the piranha article, FAQs posted on WWM?> The fish store suggested that feeding him live fish might be causing it <Yes> so we feed him defrosted silversides and try to clean up anything he doesn't eat. Is there anything you can do in a fresh water tank kind of like adding live rock to a salt water tank? We try to change a couple of gallons of water every two weeks or so. Thanks for your help, Vanessa and Frank <In this size tank... you should have redundant circulation and filtration... Do you monitor aspects of water quality? Much not stated in your mail here... Do see WWM and write back if you have further questions. Bob Fenner>

Piranha Questions Sorry to bother you again, but you've been most helpful. . . The room that my tank is set up in unfortunately had plumbing problems in the ceiling from the bathroom above and was exposed to mold. . . about a week later I noticed similar growth in the tank and have since lost three of my five previously healthy baby piranha- what appeared to be a very rapid fungus growth on the fins/eyes. They died during treatment. <Mmm, highly unlikely that this is related to the room mold problem> The two left are about 1" and seemingly very healthy. I have since transferred them (temporarily) to a community tank w/ similar water conditions- minus the growth. They're actually more social in this MUCH smaller tank and are accepting more types of food as well. . . although a couple fish belonging to this tank have already fallen victim to some nasty fin bites! At this size the piranha seem to have similar mannerisms to their tetra relatives, although their relatives are about 2x the size! <Yes> I'm thinking about leaving them in the community tank for a while longer to get them accepting other foods and to be sure they're healthy before returning them to their larger tank. Is this ok if everybody seems to socialize well for now? There are tetras and some aggressive Gouramis (male/female) in there now w/ them (a Rose Barb too, but I think he'll be gone shortly because they've been picking on him. . .) everybody else is fine. <Mmm, well... you'll likely lose some livestock...> Eventually I will have to transfer them back to the proper size tank since they're growing- I've treated the room and have done my best at restoring the tank (changed water/vacuumed/treated w/ Melafix/increased flow & aeration) is there anything else I can do?  <I would leave off with the "Fix" material. More trouble than it's potentially worth> It's been two days so far since they've been out and I've cleaned up the tank- how long should I wait before returning them? <A couple weeks.> I would also like to add another 3 fish once I know the tank and current fish are healthy, and I'm assuming this is best done while they're this small (??) <Yes> I want to keep a healthy shoal of 5- I've already owned a single piranha in the past and want to see the difference. . . THANKS, Aja <Much more natural behavior, interesting social interaction in a group... How big is this tank? You need at least 25 gallons per individual... Bob Fenner>  

Re: Piranha Questions Well "their" tank is 30 gallons for now. They're 1" at the moment. <For five piranha of this size... dangerous. Do keep them well fed...> I have a 50 gallon designated for them once they're a bit bigger and will be investing in a large enough aquarium for them when the time comes to move from the 50 (I'm assuming that'll be sometime next year?) <Perhaps sooner...> I'm sure I'll lose some fish while I'm waiting for the tank to clear up and be safe. . .is there anything else I can do to be sure this won't happen again? <Redundant filtration, circulation...> The water conditions were not great (hard, and low pH) but everything else Ammonia and Nitrates, etc. was at 0. What do you think would've caused this?  They were perfectly healthy for a week and rapidly deteriorated over the course of two days. I know they're fragile at this size, but. . . Thanks, Aja <Perhaps some unknown change in water quality, maybe something "got into" the system... an aerosol, cooking oil cover on the water, window cleaner... Bob Fenner>

Piranha Illness  10/2/05 Hi! I have a Red-Bellied Piranha that I have had for 5 years. He has done well up to this point. Just recently, I've noticed that he has been swimming on his side and upside-down. I was afraid that he might have something like gill flukes. I'd hate to have him die if I can do something about it. Thanks! <Mmm, not gill flukes or any pathogenic/biological cause unless you've introduced the vector through feeding contaminated food/s. More likely environmental... I would (very quickly) check your water quality and whatever it shows, start large daily water changes (like 30%) with water that this fish lives in (soft, acidic, low nutrient load, warm). Bob Fenner>

Piranha injury  12/14/05 Hi! I have a 5'' red-bellied piranha that has a swollen chin. It has large bumps on it's chin as well. I think it is because it has been running into the glass often, <This often happens... Piranhas are quite "skittish" species... particularly if housed alone (most are schooling fishes) and rub their faces, run into tanks...> but I'm not sure. I'm wondering if there is anything that I need to do to treat it, and if I can prevent it from happening again. <Most treatments I'd avoid... more risk than they're worth in this case> I was thinking about putting more plants in the aquarium to help it feel more secure so it won't bump into  the glass all the time, but am still not sure that it isn't some kind of disease. Thanks for your help! <The plants are a very good idea (do watch your hands if/when in this tank... Bob Fenner>

Piranha cloudy eyes   2/6/06 Hi, <Hello>    I just setup a Piranha tank with three to start off. The tank has been setup for months with other fish, witched <"The house began to twitch..."> I removed to another tank. after acclimating to the new tank I noticed that two of them had cloudy eyes. They seem to be acting fine and all three are eating prawn. Could this be from the transporting them from the pet store to my home and the stress of it all? <Yes> any suggestions on what I can or should do, looks like they have a cataracts or something. The tank size is a 29 gal high, temp is 75 degrees with plenty if plants. I do have hood lights but I am using a top floating plant to defuse some of the light. Best regards. William <Mmm, what is the water quality here? I suspect this is where you're off. Simply fixing pH, alkalinity, raising temp. will likely "do it" here. See WWM re Serrasalmines. Bob Fenner>

Senior Piranha  1/8/07 Hello Mr. Fenner, <Sorry Denise, not Bob--just Pufferpunk here--hope I'll do...> I was reading over your FAQ's page.  I have had "Fred" my red bellied piranha for approximately 16 years.  As of recent, I noticed him getting a spurt of swimming energy and then all the sudden falling over on his side.  It is almost like he can not keep his balance.  He will lay up against the side of the tank for hours. He breaths "heavy and fast".  Not sure if this is common in piranhas.  I want to help him, if there is something I can do.  I do frequent water changes, keep close eye on the temp, and make sure the filters are cleaned at least once to twice a week.  Is there something more I can do?  It is not like I can put him on a leash and take him to the vet?  Any suggestions? <I'd have to guess old age with this fella.  Quite a feat, keeping a fish that long!  Just keep doing what you're doing & keep him as comfortable as possible.  Might want to back off feedings a bit, as his metabolism is slowing down. ~PP> Denise in PA

Piranha With Gill Cover Deformity Hello its Tara here. I contacted you before about the set up of my new tank and like you suggested we let the tank cycle for longer and now have our red   bellies. When we got them they didn't have any color but now have red bottom   fins They are about 4 cm long now so should they have a red belly by now We   have been giving them a varied diet. Also one of them has a slight stuck out   gill, we asked the pet store if this was an illness but they said it is probably  a slight deformity( I don't think they have a clue) so is there something I  should look up and check? < I happen to agree with the store. Deformed gill covers are not that unusual in captive bred fish. Most of the time they are culled out before they are shipped.> Other than that they are fine and I have no other worries. While they are small we have put in a Pleco to help with the cleaning of  the tank. He is massive I was just wondering if they will eventually end up eating him? < They love fins and if they think he is a food item then they will continue to pick at him. He may go into hiding and only come out at night when the red bellies are asleep.> Lastly, one more silly question when do they start getting their teeth or  are they just to small to see at the moment? < The teeth are in, they are just small.-Chuck>
Thanks again. Tara

Old piranha -- 07/18/07 Hello! <Hi.> My husband and I have a piranha that we believe to be about 10 years old. He's kept in a 55 gallon tank and is the only fish in there. He has always been in good health, but about three weeks ago he started swimming facing down. Then a little over a week ago he started to lay on the bottom of his tank and not swim at all. His coloring is still good, but he barely moves during the day. We noticed that at night he tends to swim around a lot more. Could it be possible that the water in his tank is too hot? We have AC in our house, so his tank is usually as warm as 82-84 degrees. <Temperature is ok, 86 F is the upper limit for piranhas, 79 F the lower limit.> Is this what is causing him to act so sick or do you suppose he has some other illness or is simply getting old? <Likely the latter, while they can live for more than 20 years, 10 years is not a small age for a captive specimen. Also check your nitrates and pH to exclude those two environmental factors. You may want to introduce some floating plants to make him feel more comfortable during day. Usually they live in small groups, but I would not add further specimens to your old fish. Have a look at: http://www.wetwebmedia.com/FWSubWebIndex/piranhafaqs1.htm.> Thank you! <You are welcome. Good luck with your piranha. Marco.>

Red belly piranha, hlth., beh.   ~ 01/12/09 Hello I was wondering if you could help me with a worry of mine. I have four red bellies about 5 in in length and they have been doing fine up until about 4 days ago. They are acting normally but they lose their vibrant red bellies at night I never noticed it before maybe it's been that way at night but I never noticed it. Their water temp Is maintained at 82 F and their water ammonia and nitrate levels are normal. I did however take out a piece of driftwood that sit in the middle of the tank but they were too big to swim into it so they never used it. Any ideas? Joel <Joel, it is perfectly normal for Pygocentrus nattereri to change colour at night. They also change colours as they mature. It is quite possible that they've always had different colours at night, but they're getting to an age now where these differences are become more pronounced. You're keeping your fish a little on the warm side for this species, though piranhas from the rather warm Rio Xingu do indeed like things a bit hotter than otherwise. If you turn down the thermostat a notch, not only will there be more oxygen in the water, but your fish will also live longer and be less aggressive towards one another! The 23-25 C, 73-77 F is just fine for them. If in doubt, visit Fishbase to check the temperature preferences of your fish; for some reason I cannot fathom, a crazy proportion of aquarists keep their fish far too hot, wasting money and compromising health. For what it's worth rather than worrying about bogwood, use plants to provide shade for these light-phobic fish. Tall plants, such as giant Vallisneria and big Java ferns are ideal, and floating plants with long roots like Amazon Frogbit work very well too. Piranhas are primarily dusk/dawn fish, and they despise bright light. Cheers, Neale.>
Re: Red belly piranha  ~ 01/12/09
Thanks Neale I appreciate the help! A lot of websites for piranhas suggest 80+degrees but I see the logic in your explanation. This might be a silly question but is it at all possible for a red devil cichlid to cohabit a large enough tank? And if so what size is needed for such a thing? Joel <Hi Joel. There are very few Piranha web sites I trust. Too many people keep these wonderful fish badly. Like Rottweilers and pit-bull terriers, they have this image of brutality and so brutal people end up keeping them. But just like those dogs, kept properly, Piranhas are fascinating and rewarding pets (as well as very beautiful, in their way). Anyway, one of the best sites is the Oregon Piranha Exotic Fish Exhibit site, a semi-academic site with a ton of good information. Here's their Pygocentrus nattereri page. They report wild fish tolerating remarkably cool conditions, for short periods at least, but do recommend low 20s C (low to mid 70s F) as the optimal temperature, and this meshes with what Fishbase reports too. By the way, don't change the temperature all at once, but just knock it down a degree every couple of weeks, and watch how your fish react. http://www.angelfire.com/biz/piranha038/nattereri.html  Now, as for tankmates. I have seen Piranhas cohabit with Convict cichlids, but what we see in these situations tends to be a dominant cichlid that terrifies a small group of Piranhas. Because Piranhas are nervous at the best of times, I just don't see any mileage in that, and would recommend keeping the Piranhas on their own. Sometimes Suckermouth catfish like Plecs coexist, but that usually depends on the Plec being their first, so the baby Piranhas grow up with it, accepting it as part of the furniture (rather than food!). Adding a catfish to an established tank is just too risky, and I don't need to tell you that Piranhas have a lot of firepower at their disposal should they decide to turn on a tankmate. When all is said and done, my advice is to keep 'em alone. A nicely decorated Piranha tank is a thing of beauty, just as it is. Cheers, Neale.>
Re: Red belly piranha
Thanks for all the help Neale you've helped a ton Joel <Happy to help. Cheers, Neale.>

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