Originally posted by TaffyFish
so are there different genus of piranha reflecting the differing natural habitat? I would imagine the longer body shape is better suited to faster flowing rivers whilst the more compact is adapted to slower waters?
Well, both genus occupy the same water...Pygocentrus Piraya and Serrasalmus Brandtii are found in the same river...but have totally different body shapes. Same goes with every other river system that contains Pygocentrus...there will be some species of Serrasalmus which is typically more compressus than Pygos. That being said, you are correct that in the faster moving waters the piranha species that occupy them are typically serrasalmus and much more compressus. S. Elongatus is a very streamlined piranha, much more elongated than any other species of piranha, and they are found in 2 types of water...fast moving river, and lake water....go figure....lol
from your description of the irritans behaviour it sounds like he thinks his territory extends beyond the limits of the tank - do you have any idea how much territory they occupy in the wild and does this give you a basis for understanding the tank sizes required for captivity? even if you haven't observed them in the wild I assume you have access to research? does the piranha world have an Ad Konings?
S. Irritans is a nasty little fin nipper. I do not know how much territory the occupy in the wild, there is not a lot of information on this species. They are a very small species though..and very fast.
As far as research, you would be suprised at the lack of research done on the piranha species. It is in its infancy so it is very hard to find any creditable information...another reason piranha-fury is so popular because for the hobbiest, it is by far the most accurate information you can find. Having Frank Magallanes of OPEFE is an amazing resoruce for information because he is in contact with the scientists in the field. I dont know what Ad Konings is
are there accepted male to female stocking ratios, and at what relative size can juveniles safely co-exist with adults?
there are only a few species of piranhas that are sexually dimorphic....so you really dont now if you have males or females unless they breed. For the most part, you dont want to have a large spred in size with smaller piranhas. You have a much greater chance of loosing fish that are under 5". Smaller fish are much more apt to take out a roommate than larger fish. This is also dictated to the personality of the individual fish. I had some 11-12" terns that were fine with a 6" red...but this red is a very aggressive fish...I dont think it would be wise with a more docile fish. It is always better to try to get fish around the same size when creating a shoal because aggression is always heightned when they are establishing a pecking order in the tank.
I've seen serra's kept at an lfs in rows of barrack tanks barely big enough for them to turn around in. would you have to keep such a fish on its own in a 55 or 75 and would it then swim around the tank or remain motionless - I guess I mean what's the chicken and the egg here - the fish's limited movement or the constraint of the tank size?
Once again you are dealing with the individual fish. Serrasalmus are almost always kept as a single species. S. Geryi, S. Spilo and S. Maculatus are basically the only Serrasalmus that can be kept in a shoal, but many people have lost fish attempting this...and when dealing with S. Geryi and paying 150.00 for a single 4" fish...it is a risk. I have had my geryi shoal together for over a year without loosing a fish, but I have had some pretty bad injuries that required me removing the injured fish to heal in a seperate tank...but nothing that has not healed *knocks on wood*
When you get a serrasalmus, for the most part you are getting a show fish. They will almost never be as active as a shoal of fish. I have one fish in a 120 gallon tank and I can watch him for hours and find him amazing...but that is me and not for everyone. Piranhaman has a 7" brandtii in a 75 gallon tank and it is a great tank imo...it is all up to the individual fish keeper and his or her interests.
