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FAQs on the Piranhas Compatibility

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

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


Piranha; stkg., comp.     3/4/16
Hello crew
I am restocking my 90 gallon with predators to take care of my surplus of feeders that I breed. I was thinking red belly piranha with a school of Exodon paradoxus. Thoughts?
<Much as I like Exodon paradoxus as a vastly better aquarium fish than Serrasalmus and Pygocentrus spp., the two types of fish don't cohabit. Larger piranhas will always be a potential predator on smaller fish like
Exodon, but conversely, Exodon are boisterous and nippy enough they could threaten the much more nervous and easily startled piranhas.>
Is this possible?
What are my other options here for toothy predators?
<Rocks, plants, plastic skulls, that sort of thing. The reality is that piranhas are not good aquarium fish, their sensitivity to poor water quality and their inherent nervousness making them much less adaptable than their Hollywood image might suggest. Like other experienced aquarists I've seen piranhas living with Plecs and even convict cichlids, but these situations are memorable because they're exceptional. Piranhas are simply
better kept singly (if a non-schooling species) or else in the largest possible grounds (for the more sociable species). If your tank has space, either relish the fact water quality management is easier or increase the
size of the school of piranhas you're keeping (with the usual caveats about only combining the same species and similar sized specimens). To be clear and re-state the central message here: a piranha aquarium is a dull
aquarium, and your piranhas want it that way. They're basically boring fish that need a dark, quiet aquarium to be happy. Now Exodon paradoxus, on the other hand, is far from boring... though they can't really be combined with anything else, and you do need at least a dozen, and probably twenty or more, if you don't want them to kill each other!>
<Most welcome. Neale.>
re: Piranha     3/4/16

So scratching that idea are there any other good predatory fish that can work here? Wolf fish? I have kept most oddball fish and currently have a lot but nothing with actual teeth.
<It's not really a question of skill, but rather the fact Piranhas make terrible co-habitees. Even if kept with something they wouldn't kill, they're so easily spooked the Piranhas become stressed and more prone to
the sorts of behaviours that cause physical damage to each other or their tankmates. Invertebrates are obviously an option, snails, crayfish and things like that, assuming they're not bite-sized (so not Cherry Shrimps).
Such animals aren't really on the menu for Piranhas, and being slow-moving, they're don't spook the Piranhas. Of course you will see some of the Piranha forums recommend Plecs and Thorny Catfish, but often with a comment along the lines of "luckily these catfish are cheap in case something goes wrong...". Not sure the poor catfish would be quite as phlegmatic! Ditto big but docile cichlids such as Oscars. So really, advanced aquarists
simply accept the fact Piranhas are dull and work around it. It's never going to be a fun tank, but it's a specialist tank for studying these undeniably interesting characins. But if you're after an interesting oddball aquarium, well, that's another tank... make sense?>
<Most welcome. Neale.>
re: Piranha     3/5/16
What would a good predator be for this tank to take care of the surplus?

<I'm not sure what you're asking here. If you're breeding killifish or livebearers in another tank and have ridiculous amounts of fry, then an obligate piscivore like a South American Leaffish or Pike Livebearer in its own tank might be one option, though you'd need a very, very stable supply across many years to keep these types of fish. If it's just the odd batch of cichlids or Corydoras you're breeding, then just pass them on to your
local shop or aquarium club? Ditto if you've got surplus piranhas then you could surely sell them? And to be clear, I'm 100% against the idea of keeping predatory fish simply to stage "fights" where one fish eats
another. It's neither a good way to keep piscivores (increases aggression; exposes them to pathogens; not nutritionally balanced) nor ethical (causes stress and suffering in the prey). Cheers, Neale.>
re: Piranha     3/5/16
I have a large amount of live bearers.
I didn't realize that they would breed so quickly and I cant do anything else with them. Thanks
<Got you know. Then something like an African Butterflyfish might be an easy to obtain choice, but South American Leaffish would be a great companion for these and really interesting to keep. You'd need to supply
the Leaffish something like a dozen half-inch fry a week, and they generally eat nothing else besides tiny fish, so you really do need a production line of livebearers! African Butterflies will eat any fry they find, but also take wingless fruit flies and other small insects easily obtained from reptile shops, so they're much less difficult to keep. Some will even take decent flake and pellets too. Cheers, Neale.>
re: Piranha     3/5/16

Ok. Once again thanks for your help neale!
<Glad to help. On reflection probably underestimated the amount of food needed for Leaffish, to be honest. Don't need feeding every day of course, but they'd probably get through half a dozen half inch fry in one sitting,
perhaps three or four times a week. Oh, and do look at Leopard Bushfish too. Lovely fish. Cheers, Neale.>

Piranhas   2/2/15
Quick question, I have 3 juvenile red belly piranhas in a 80 galloon bow front, I also have 1 adult red belly in a 29 galloon.
<What's a galloon?>

I do feel bad that the adult just sits in his cave(s) and is lonely and doesn't have another buddy. I wanted to hear you're opinion if I could stick the adult with the 3 juveniles in the 80 galloon. Would it be safe?
If not than that's fine It's better to be safe than sorry.
<Depends on relative size... if more than an inch, I'd not mix. Even IF all the same size; will at times bite chunks out of each other. Bob Fenner>

Snails and Piranhas?   1/18/11
Hello again. You helped me so much with how to care for my piranha! Thank you! Now I have another question... I was just wondering if I introduced a few snails into my tank if my piranha would eat them. Him and my Pleco have never bothered each other, but they were raised together. I love snails, and really want a few in my tank, but I don't want to wake up to find a half eaten shell. Thanks so much for your help!
<Piranhas generally ignore small snails, but larger ones like Apple Snails with long tentacles might be nibbled on, and once damaged, those snails quickly die. So either add some cheap pond snails such as Physa spp. snails, or else choose armoured varieties such as Nerites that won't be easily damaged. Cheers, Neale.>

Piranha with cichlid   8/5/10
I have 120 gallon and a 55 gallon tank with 3 Cariba Piranhas.
<Pygocentrus cariba, a somewhat aggressive member of the genus. Do understand that while gregarious up to a point, this species is notoriously snappy, and I'm surprised your trio are getting along so well. Larger groups usually work better. As I'm sure you know, Pygocentrus tend to be more hierarchical when young, and full-grown adults can be fairly mellow, and the tricky part with a group is getting them there. Do also remember this species is partially herbivorous and adapt its diet accordingly; a common mistake people make with this species is to leave out a source of fresh greens, such as floating Indian Fern. As with all piranhas, don't use live feeder fish and avoid fish meats rich in Thiaminase.>
I'm going to put the Caribas in 120 gal and wanted to try to put some cichlids in the tank with the Caribas.
<Not a chance.>
wanted to know if this is possible if so what cichlids can defend themselves against them.
<None. Cichlids, particularly their tail fins, are natural food for this species. Probably like you, I've come across tanks where there's a single Convict Cichlid bullying a bunch of Red-bellied Piranhas. But generally that doesn't work. A bullied Piranha is an unhappy Piranha; these are incredibly nervous animals that adapt poorly to home aquaria anyway, so anything you do to stress them shortens their lifespan. In really big public aquaria you do sometimes see them kept with livebearers; I've seen Piranhas mixed with Guppies and Ameca splendens for example. Here the livebearers operate as dither fish -- not really as live food -- encouraging the Piranhas to swim in the open more confidently. The problem is that in home aquaria the space for two species to coexist just isn't there, and half a dozen Guppies will end up eaten or worse, multiply so rapidly they become an unwanted nuisance. Bottom line, Pygocentrus cariba is best kept amongst its own kind. One last observation: this is an extremely dangerous species known to bite, so please do be careful. Cheers, Neale.>
Re: Piranha with cichlid   8/5/10
Thanks. I guess I will put the cichlids in a separate tank.
<Good idea.>
My Caribas are strange I can keep Plecos and crayfish with them but I put a divider in my tank and put a Saber Tooth Tetra in it and one of the Caribas jumped the divider and chewed the Saber Tooth in half.
<Yikes! For what it's worth, Hydrolycus scomberoides has an abysmal track record in captivity. It certainly needs a huge aquarium with extremely strong water current and masses of oxygen to do even halfway well. It's
common for them to seem to thrive for six months or more, and then just keel over and die overnight.>
Oh and as them being dangerous I found that out the hard way about a year ago one of them took a dime size chunk out of the base of my thumb, after that I always use tongs.
<Indeed. The use of live foods tends to make fish more aggressive, but since you're using tongs, I assume you're feeding them Thiaminase-free seafood and tilapia fillet.>
Thanks again
<No problem. Enjoy your fish! Cheers, Neale.>

Piranhas, comp.  -4/7/10
Hello, I have a 6 or so year old Red Bellied Piranha. My mom started with 4 and over the years, they just died off.
<Aggression. Red Bellied Piranhas (Pygocentrus nattereri) must be kept in groups of six or more specimens if you want a group. In smaller groups they invariably turn on one another.>
I now have the sole survivor all alone.
<Completely predictable.>
He is in a 40 gallon tank
<Too small.>
and I am wondering if I can introduce another adult piranha to the tank.
<Not a chance.>
If not, I am content keeping Chompy all alone.
<After a fashion.>
He seems happy chasing the dogs tail across the aquarium as he walks by. If you think I can though, how should I go about this?
<You can't. The specimen you have needs a bigger tank simply to do well.
Groups of six or more specimens need tanks around 200 gallons upwards.>
<Cheers, Neale.>

Piranha I have a Red Belly Piranha, about 6 months old. I want to know what kind of fish can go with him. I had a Red Devil that was bigger than him in the tank. The tank is 20 gallons. <Sorry, but there is nothing else you can house in a 20 gallon tank with a Piranha.> The Red Devil went after the Piranha. The Piranha did not fight back when I saw them fight. One day I went to look at the tank the Red Devil was in half. I want to know what fish if any can live with him. Thank you, Mike <Have a nice night. -Steven Pro>

Possible Piranha Partners Hi! I have a 2 inch long piranha in a 10 gallon aquarium and was thinking about moving into a larger aquarium and possibly adding 1 or more piranhas his size. Do you think I could do that without the piranha nipping or killing the other piranhas? <Lot of different species of Piranha out there. I'm going to assume we have a Red Bellied. Colorful, mean and (too) commonly sold. Well fed Piranha [I] usually[/I] will not kill one another. In the wild they do travel in schools. In the confines of an aquarium the danger levels increase. If you are looking to produce a large display quality fish I would recommend you keep him alone. If nipped fins, missing scales (or worse) does not bother you then get a couple more of the same species. I would either keep one or a school of 5 or 6. This will spread out the damage if one or more are on the aggressive side. But if you want a school, you will need a MUCH bigger tank. 150 gallons or more with great filtration. Your single would do well in a 55 for many years. You could get away with a 29 for awhile, but you will have to upgrade in time anyway. Red Bellied Piranha get huge. Dinner plate to serving platter sizes are possible. One more point. Please do not offer them feeder fish. You WILL, not may, introduce Ick or worse into your tank. Train them to take human seafood, worms, insects. Stay away from land animal meats. Any freshwater seafood, including feeders, should be frozen for a few days to kill off bacteria and parasites. Good luck. Don>  

Tankmates for Piranhas Hi, I'm thinking of getting a 100 gallon tank and about 4-5 piranhas (red bellied). I was just wondering if algae growth is a problem and could I add a Pleco to the group to clean things up? Or can I get a filter that is strong enough to get rid of all the algae and keep things clean? One more question. Can I keep plants with piranhas? Or will they destroy them? And if any plants are toxic to piranhas. Because I wanted to make a tank with plants to cover some of the light because piranhas hate bright light and can't stand it. Thanks, your web site is very useful! <A big Common Pleco "may" be able to live in this tank. Give him a cave to hide in during the day. But in the close confines of even a large tank anything can happen. They are poor algae eaters as adults anyway. So I wouldn't stock one. You're going to need tons of filtration and an algae scraper I think. I suggest a scraper that will not require you to reach in the tank. Floating plants should be OK. Don>

Piranhas With Oscars  12/9/05 Hi Wet Web. I have a question relating to what will happen if I introduce piranhas into my tank. I currently have too palm-sized (about 7") tiger Oscars in my tank and am thinking of introducing maybe 1 or 2 piranhas to the mix. I am curious as to what will happen between them and whether one will dominate the other or whether they are both strong enough and aggressive enough species to get along with one another. Thanks for your time. Pete < Piranhas are much more confident in groups. As a single fish or even a pair I think the Oscars would push them around. Much depends on the species of piranha and the sizes of all the fish concerned. In the wild piranhas pick on Oscars all the time. Wild Oscars have developed a black spot near the tail to look like an eye to the piranhas so they won't be able to tell which end the mouth is at.-Chuck> <<RMF strongly believes the Oscars will end up with chunks missing>>

Piranha system, compatibility question    1/19/06 I had 2 red bellies in the same 55gal for about 4 years, I bought the 2 at the same time as small fish, and they grew up to be about 8-9in in length. I had to leave town for an emergency and when I returned home, one was beaten up pretty bad. <Happens> I had been gone for 3 weeks, and they had not been fed while I was away. The hurt one wasn't able to recover. Now the survivor just sits in the corner of the tank, whereas before the 2 swam around all the time. Are there any tank mates I could introduce into the tank? <Not likely... though if this tank were much larger, I might try adding the larger one to it... with a physical barrier (like louver) separating it from the rest/others... for a few weeks. In such a small system as the one is currently in, it is almost assuredly going to attack anything that "invades its space". Bob Fenner>

Piranhas, comp.  - 04/05/2006 Hi, My name is Brent and I have 3, 3inch Piranhas... my question is, is it possible to add young piranhas in the same tank as the more mature ones, or will the older piranhas eat the little ones. thanks Brent. <Most species of piranhas will bite, consume each other if hungry... All species need a good deal of room per specimen... twenty or more gallons. Bob Fenner>

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

RB Piranha comp.   - 04/20/07 Hi Bob, <Well, it's actually Neale, but Hi anyway!> My son purchased some red bellied piranhas (Babies). <I trust he bought a book about piranhas first? These are neither easy fish nor ideal fish for beginners. They are also rather large and basically boring pets. Great for people with space and experience, but terrible for children.> However two smaller ones keep attacking the larger one. <Absolutely normal. As any book about piranhas will tell you, these are intensely hierarchical schooling fish that live in swarms of hundreds of specimens. When kept in twos and threes their normal behaviour is short-circuited and the dominant fish *invariably* ends up bullying the one at the bottom of the social order. This is repeated as each fish below the "boss" dies, until you have a single specimen. Being schooling fish, they are very unhappy kept alone, and this singleton is nervous, flighty, and not at all entertaining.> First time they ate his fins, tail and took out an eye (hence his name eyeball). I got a divider so that eyeball could recover which he did. Today however, the two smaller ones again attacked eyeball eating his fins and tail. Eyeball can not stay in an up right position, so again I put in the divider and have eyeball suspended in a net in an up right position. I have kept him alive now for 11 hrs, but was wondering how long I should keep him in the net? <Well, piranhas heal very quickly when in good condition. They have to: their mating rituals (if you can call them that) involve biting chunks out of each other. But as should be glaringly obvious, there's no way that "Eyeball" can ever be kept in the same tank as the other two specimens. Oh, and it's probably a matter of time before they fight. So be sure and get three large aquaria set up, one for each piranha.> Should I keep him there till I see signs of re growth of his tail? <Yes. And also when the wounds are nicely healed. And I'd keep treating the water with something anti-microbial, such as Melafix.> I feed them plenty (shrimp, fillets, snails, krill etc...) just do not understand why they attack eyeball. <As said above: from being kept in appropriate numbers. They are doing what comes natural.> All the fish are healthy otherwise.. At this point I do not want eyeball to pass away (so much work has gone into keeping him alive) water conditions are right on target.. Not sure if keeping him in a net in the up right position is the best idea, but at least he is not laying on his side on the bottom of the tank. Any suggestions on how I can help him heal quicker so he is not confined in the net but is still up right? <Sounds to me you're doing the right things in terms of triage. But keeping him in a hospital tank is probably the best route, and actually inevitable really because this fish will have to be kept apart from the other for the rest of its life.> Thank you so very much for having a wonderful site for people to use as a reference. <No problems. Glad to help. Now please, sit down with your son and discuss the future. A "safe" number of specimens is 4 in a 75 gallon tank. You can keep more than that, adding around 20 gallons per specimen. If this isn't on the cards, then your son may need to think about re-homing these fish. If he wants something piranha-like, Exodon paradoxus is easy enough to obtain, but smaller, and just as fierce; it's also prettier and more active, and will even eat flake. Finally, please make sure he isn't using live feeder fish for food. That's a sure fire way to introduce parasites and pathogens. Goldfish and minnows also have serious nutrition problems because they contain Thiaminase. The only safe feeder fish are livebearers bred at home. But with piranha you don't even need those, and your fish will be healthier given a pellet/stick staple diet carefully balanced to have all the nutrition fish need. Augment periodically with "treats" such as frozen silversides and lancefish. There are plenty of good books about piranha, and as a good mother it's up to you to teach your son about research and responsibility. Too many young boys buy piranhas because they are "scary" and then suddenly discover that, like all animals, they have needs and must be cared for properly.> Dar

My new tank, poor FW mix of lvstk., ich   1/31/08 hi, Currently I have 55G tank which contains four 2inch gold fish , six 2inch koi carp , two 4inch koi carp , six 2inch angels and one 25cm Pleco. I know it's a small tank ,that's why I am building a new 200G tank. <Very good.> I am thinking about buying 2 red bellied piranha. Is that a good idea?. <To mix with these fish? Absolutely not. In addition, most of the common piranhas in the trade, including Pygocentrus nattereri (the Red-bellied Piranha), are essentially solitary fish in aquaria. Their social behaviour in the wild is extremely complex and difficult to replicate in captivity. Juveniles may school together, but adults only form schools under certain conditions, and when mature the males are territorial and ultimately guard nests and eggs. Unless kept in BIG aquaria where there are AT LEAST SIX specimens, piranhas simply don't work in groups. The dominant male systematically harasses and eventually kills the other fish. The flip side to this is that single piranhas are nervous and scared of their own shadows! They are very VERY boring pets.> Is there any kind of fish that I can add with the piranha's? <None.> Right now I have one more problem , one of my koi carp is scratching ,what should I do . <Likely Whitespot/Ick and should be treated accordingly.> Is it necessary to remove live plants before adding any medicine into the system?. <Not normally, no.> One of my koi carp has full red body with small white patches in the middle, is that what u call white spot disease. <Sounds like it.> And last I want u to suggest a suitable filter for my new 200G tank (please mention the company name also) <The ideal filter will vary. If the tank contains just fish and no plants (or maybe floating plants or plants attached to wood) then an undergravel filter can work very well. Use at least two powerheads to get a gravel bed this size working properly. Alternatively, you can use one or more external canister filters. These work better with tanks that contain plants. In either case, the brand of filter doesn't matter much, though some brands, notably Eheim, have a good reputation for reliability and value over the long term. The main thing is turnover. For large fish like yours, you want the powerheads or filter pumps to produce at least 6 times the volume of the tank in turnover per hour. So in your case, the pumps should add up to 6 x 200 = 1200 gallons per hour.> thanks a lot Mathew <Cheers, Neale.>

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