View Full Version : Stocking Tank with Piranhas...

08-22-2007, 02:08 AM
Hi All,

I have a 130 gallon tank, 6' long 18" deep and I want to stock it with piranhas. How many can I have in the tank once they reach adult size, and do they need other fish in the aquarium to maintain good mental health? Thanks...

08-22-2007, 02:15 AM
I would Say 4 or 5 Adult Pirnahas would be ok. Never put any other fish with Piranhas.

08-22-2007, 03:12 AM
Maybe a goldfish or two as a tankmate?

just kidding lol, have fun with your piranhas, they amazing to see.

08-22-2007, 03:45 AM
Dont suggest stocking options untill you know the specifics.

What is the filtration like?
What is the water change amount?
What is the water change schedule?
What are/will be the tankmates?

08-22-2007, 04:22 AM
Filtration: dual biowheel exteranl filter, "The Emperor".
Water change: Once a month 10% water change. (I wish it was more, but I'm lazy and I'm not going to kid myself, and additionally I keep my tank extremely understocked so I can get away with it.)
The current stock will be given away before getting the piranhas, so I can start from scratch. :c5:

08-22-2007, 04:58 AM
Wonder where you are, as keeping piranhas is illegal in many US states. Also, with a group you have to watch carefully, as its fairly common for one to pull a Jeckyll and Hyde and eat its schoolmates.
Also, 10 percent monthly is insufficent for piranhas as they are messy eaters who are sensitive to water conditions. Twenty or 30 percent weekly is minimum.


08-22-2007, 01:28 PM
Water changes should be weekly, and larger. The filtration needs to be increased (one Emperor 400 is not enough). I would add a Fluval FX5.

What is the other dimension of the tank, 72x18x?"?

I am so glad someone else has realized that stocking is not affected just by tank size, that filtration and water change schedule is just as if not even more important.

08-22-2007, 10:15 PM
In Maryland Piranhas and Stingrays are allowed plus almost all plants.

08-22-2007, 10:46 PM
Fishguy2727: With the setup you described, do you think that would be adequate filtration for 4 to 5 fully grown piranhas?

08-22-2007, 11:42 PM
That is really pushing it. They hit about a foot, so that is a big bioload, so the water changes would have to be big and frequent.

Do you live in Maryland?

I have heard that they had recently outlawed them in Maryland too, I do not know if that is true or not though.

08-23-2007, 12:39 AM
You need a lot more than one emperor. I would say like two XP4's or something like that would do it. I do 35% water changes twice a week on all of my tanks, with piranhas, if it is even understocked I would do the same.

08-23-2007, 12:42 AM
If I were you I'd get a python - you'll be able to change 75% a week without breaking a sweat.

08-23-2007, 01:07 AM
If I were you I'd get a python - you'll be able to change 75% a week without breaking a sweat.

Lol, yea from what he said then that is his best bet.

08-23-2007, 04:27 PM
ha ha ha...

I've thought about getting a python before, but then no girl would ever want to go into my room again.

BTW, I don't live in Maryland, so I should be fine, and I was digging around my aquarium supplies and found two more Emperors, do you think that should do it?

08-23-2007, 04:49 PM
lol, a python isnt a animal, its a aquarium vacuum that hooks to your tap and drains and refills, no buckets or effort. i love mine

08-23-2007, 05:01 PM
ha ha ha ... oops.

Therefore after you have changed out the water, do you just add all the water treatment chemicals directly to the tank?

If that's the case, I could do water changes all the time, and never have to get my carpet wet. :thumb:

08-23-2007, 05:04 PM
yep, it drains into the sink, then straight tapwater flows to the tank. when its filling slowly add water conditioner and thats it. they average at about 50$ american but pythons are well worth it


08-23-2007, 05:14 PM
I just do a full dose of dechlorinator when I start to fill again. I treat for the whole tank or system, not just the number of gallons being added. Better to have a lot extra then a tad too little. This is only at work since at home I am on well water.

08-23-2007, 05:52 PM
That's great information. And after looking at the web site, I think that I have one. I just didn't know what it was when I got all the stuff for my aquarium. How do you start the siphon? I know that I don't have any paper work for it.

My fish are going to love me now...

08-24-2007, 04:48 PM
Tried out the python yesterday. Made the water changing a breeze. It's basically just one long siphon. I think it may have been the first water change where I didn't get the carpet wet. :19:

08-24-2007, 11:29 PM
Tried out the python yesterday. Made the water changing a breeze. It's basically just one long siphon. I think it may have been the first water change where I didn't get the carpet wet. :19:

I always get mine wet.:9:

08-26-2007, 04:47 PM
when it comes to filtration for Piranha's you should try to filter all the water in your tank 10x an hour or more.. So in your case for a 130g tank you should try for 1300 GPH(Gallons Per Hour) combined filtration. What Model Emperor/Emperor's do you have? What kind of media are they filed with? With the right media Three Emperor BIO-Wheel 400's could work. That should be close enough, about 1200GPH Total. Before you decide to get Piranha's you should know that thereís alot of work involved! Water changes every week, removing uneaten food, Quarantine tanks for feeder fish or weekly trips to the fish market, constant filter maintenance, not to mention they can be expensive to feed. Iím not trying to discourage you or anything. I just want to make sure you know what youíre getting into. Let me know about those filters so I can help you with more accurate information, alright bro. Good luck...O buy the way how wide is your tank?? With Piranha's width is much more important then height.

08-26-2007, 04:52 PM
I always get mine wet.:9:

lol, same, when i used to use the bucket way besides my python. my toads water gets a funky smell and once i had the bucket full and tripped and spilt it ALLOVER, then my cicket jar fell and it was cricketfest '07

08-26-2007, 05:42 PM
Lol, I used to keep crickets and raise them because I had a butt load of lizards. They would get out all the time.

08-26-2007, 05:49 PM
I wouldnít mind cleaning up the water, but the jar full of crickets would suck!! big time. Why is it that when ever a cricket gets loose they always end up in your bedroom somewhere, chirping you insane while your trying to sleep?.?.?LOL Revenge Of The Cricket...AAHHHHHHH!! His Family Was Taken!!! Feed To The Fish Buy An Evil Villain!!! Now He's Back!!! FOR REVENGE!!!!!!!!!! LOL HEHE

08-26-2007, 05:55 PM
lol, it SUCKS. im in the basement most of the time and before stores came out with the dial-a-lid things where its easy to feed i had to get the bagged ones. they would constantly get out and CHIRP CHRIP CHIRP at night. so annoying.

08-26-2007, 06:15 PM
Do not worry about gallons per hour when picking filtration. Moving water does not clean it. You need filtration, not pumps. Pay attention to what the filter claims it can handle, then cut that in half and that is about what it can actually handle. That is your starting point. If you have dirty fish or a high bioload, you need even more filtration.

08-26-2007, 06:19 PM
I stand by my two XP4 idea. Fishguy is right as always.:c3:

08-26-2007, 10:24 PM
When did I say pumps? And GPH is very important ,it determines how many gallons of water well be CYCELED THROUGH THE FILLTER every hour! Witch by the way is how the manufacture determines what size tank(Size in Gallons) the filter is capable of handling.....For example an Aquaclear 500 can PUMP a Maximum of 500 U.S. Gal through the filter in one hour & is labeled for use on 160gallon tankís. now do the math that means the entire contents (All the Water) in a 160gal tank well be filtered around 4X an hour. Now would you say that 1 AquaClear 500 could handle a 130gal Piranha tank by it self??? I would say no, more like two or three AquaClear 500's.Now lets see, how many times would two AquaClear 500's Filter the entire contents of a 130Gal?? 4+4=8 So Around 8x an hour with two AC500's pumping 1000GPH(Gallons Per Hour).Now am I crazy or is that pretty close to the 1300GPH or 10x an hour I recommended earlier?? Witch is why I ask WHAT"S THE DEAL?? I may be new to this board, but Iím not new to the game....

08-26-2007, 10:46 PM
Focus on rating, not gph. The AquaClear 500 is now the 110 (as in 'up to' 110 gallons). That means it is worth about 55 gallons of a moderately stocked community tank. If you focus on rating you will inherently get the flow needed. The best analogy to gph versus rating is quality control on a conveyor belt. On the conveyor belt of final products at a factory you have quality control. If that belt is running fast (high gph) you will probably miss things. If you have more people doing the inspecting (more filter media) the final product will be even better (the returned water to the tank will be cleaner). For a given gph the amount of media will determine the rating, not just the gph. So if you increase the media capacity you will increase the rating of that filter even though the gph was not increased. You will get cleaner water being returned to the tank with more media on the same gph. If you focus just on gph, or even worse try to avoid reducing your gph, you can end up moving lots of water without doing much on cleaning. Again, moving the water (gph) does not clean it, filtering it (rating) does. Obviously you do need to move the water enough to get the waste to the filter, but with a good filter this usually does not require as much flow as you would get if you focussed just on gph.

08-26-2007, 11:52 PM
That is why I asked what model Emperor's he has, and what types of media he's using. No matter how you slice it your way on mine they both end up with the same result. But because I choose to use a different method of reaching the same conclusion that makes ME wrong!! Wow be careful, if your head gets any bigger you might float of into space.. How about instead of cuting down other peopleís suggestions you just give your own and leave it at that?? Or did someone declare you the end all be all of Aquarium Information?

08-27-2007, 12:01 AM
i dont want to get into any war or anything but i think that fishguy knows what hes talking about and is experienced. his suggestions are what hes found BEST, not the ONE AND ONLY WAY

08-27-2007, 01:58 AM
Fortunately most filters are relatively close to one another as far as gph and ratings go, so in general most people who go by either gph or ratings end up with good enough filtration. But there is a reason why an 'underpowered' as far as gph goes filter is actually fine, it cleans better (per gph). But according to gph you would still need more filtration. The best canisters can do a lot more cleaning than a gph based filtration guide would lead you to believe. Going by gph can lead people to choose a filter with more gph over the one that is actually better. That is why I want to make sure that people focus on the one that is a better representation of the filter's capabilities.

08-27-2007, 02:46 AM
HeHe.. naw no War cocoa just a heated discussion.. Last post I donít want to keep flaming Kigroyís Post...Sorry Bro .....And just for the record I donít doubt Fishguyís experience or his knowledge on the subject and I respect the contribution heís made to the forum. Iím just saying heís being very one sided. Heís looking only at the Biological side of filtration .in a Piranha tank Good mechanical filtration is just as important, constantly moving/churning water currents DO have a role in filtration. the more water you move the more current you create. Those currents keep fish waist from choking your gravel bed, and preventing proper gas exchange thus trapping gas pockets in the gravel bed. it also prevents food particles and other debris from settling into the gravel bed and rotting, releasing ammonia and other toxins. So the faster you can filter every gallon of water in your tank the better your chances of trapping suspended particles before they settle to the bottom. That filter material also has quite a bit of surface area, and as you know the amount of surface area available is what determines a filters Bio Load...Anyway.. Sorry again Kigroy ...No disrespect fishguy:ezpi_wink1: things got a little heated & i went a bit overboard in my last post...So my apologies..heated debates are the norm in my family.. Sorry i just saw your post and your right about canisters ther just to $$.and your rite about the chances of being miss led into buying a less efective filter simply because it has a slightly higher GPH flow rate(especaly if your new to the hobby & dont know what to look for in a filter)

08-27-2007, 05:35 PM
Looks like I missed a lot while my cable was down. (Time Warner sucks! :smad: )

Answers to your questions:
3 Emperor 400s
5 or 6' wide

Thank you both for the information and the enthusiasm that you have for the hobby. :c5: I'm just a beginner at this hobby and so I have a lot of ignorance about a variety of topics. I don't know what type of media that I have in my filters. I just buy what I was told to buy. Do you recommend any particular media, and do you know of a source to buy from? And additionally, where can I find this information that each of you are enlightened with? When I got the aquarium, I read every book at the library about fish keeping, and none of them covered the details that you have all discussed here today. Is there an aquarium bible out there? (if not one or both of you should write one)

I'm most likely going to be doing weekly water changes from here on out now that I have the python. And if I do get piranhas I will up the filtration methods to the three Emperors and keep an eye out for a good deal on a canister filter as the fish grow. One thing that I am concerned about having piranhas is the timing of the feeding. How temperamental are they if they do not get fed at the exact same time daily or weekly? What is there feeding schedule? I can normally feed them at the same time everyday, but I do leave fairly often, and one thing that I like about my current setup is that I can walk away from it for three weeks, and not have any problems. Can I do that with piranhas if they are well fed prior to leaving? or will they end up eating each other, or is it a crap shoot?

09-09-2007, 04:54 AM
I'm just a beginner at this hobby

Says it all right there, why start off with such a difficult aquarium/fish?? Pirhanas are DIRTY fish, so like everyone said you're going to need very good filtration. Dont skimp out on the filtration. Theres going to be a lot of work involved and you said it yourself, that you were "lazy." I'm not trying to be rude by any means, but it seems to me that, you don't know too much about these fish and what it takes for them to live comfortably and able to thrive. If you don't know much about the fish or how they live then you probably shouldnt own them right now. Take the time to research the fish carefully THEN decide if you still want to do this. Try something less difficult, like a community tank. THEN make the leap to more of a challenge. Whatever you decide to do, good luck.

09-13-2007, 05:39 PM
"Take the time to research the fish"

What would you call posting on this forum and asking questions about them?

And in response to "I'm not trying to be rude by any means" Why would you open up your post with statements like "Says it all right there"? That's a rude statement.

Additionally, "it seems to me that, you don't know too much about these fish" That is fairly obvious (and ironically the reason why I posted on this site), but thank you for stating it.

Too everyone else: I don't like making posts like this, but I find posts like TXCichlid's insulting and not very well thought out. So I'm sorry if this offends anyone. I hope you don't hold it against me, but I had to say something.

09-13-2007, 06:40 PM
Wow, you took that the wrong way. Yes take the time to research the fish, not just here, because not everyone here has pirahanas, it's not really a common fish to keep from my understanding. . How is it not well thought out? What did i say that was so insulting?? Im not going to hold anything against anyone, it's a message board lol. You said it yourself that you were Lazy, so i said maybe you should try a different fish. Its really not a big deal..

12-04-2007, 12:32 AM
Hi All,

I have a 130 gallon tank, 6' long 18" deep and I want to stock it with piranhas. How many can I have in the tank once they reach adult size, and do they need other fish in the aquarium to maintain good mental health? Thanks...

hi i have 4 piranhas in my tank and it is only a 33 gal. they get as big as a dinner plate so i guess you could put in about 8 to 10 that way they will still have enough room to swim around. after a while if they get to big they start to eat one another..and that's not good.. I also have snails in the tank and they do just find.they keep the tank glass clean and all.they say you can get these you can put neons in with then ,but I have never done it.do you know what you are going to feed them? i feed mine chicken hearts and sometime gold fish. are you getting yours at a young age? good luck pixie

12-28-2007, 04:38 PM
I have 4 red bellied piranha in a 40 gal tank right now. There are also 2 Raphael catfish, one striped and one spotted. I change about 25% of the water each week with a gravel syphon. As of right now, I really don't think they are hard to keep at all. I have a bio-wheel rated for 75gal. I feed them 6-8 goldfish every 2-3 days. Every water change I do I add a tablespoon of aquarium salt for every 10 gallons I change, and Strss Coat. When I bought them they were about the size of a dime, and after about 6 months they are around 4-5". They are doing great! I dunno about leaving them for 3 weeks at a time. After well being well fed, I've left on vacation for a week, and they are fine when they get home. My fish will need a bigger tank though, i know that for sure! Also, something to keep in mind, they are a schooling fish. Definatly don't buy 2, as they will probably fight. I started out with 5, but one was lagging behind in growth. Eventually they ended up eating everything but his head (which is all bone, from what I understand:confused: ), My lfs said they were just strenghtening the pack. I'm not sure if this helps at all, but with a big enough tank and good filtration, they shouldn't really be any more difficult to keep than most other fish! Good luck with whatever you decide!