# Why can't...



## hyphen (Apr 4, 2004)

piranhas inter-breed? it doesn't make sense to me. completely different cichlid species can inter breed, but two piranhas can't? i mean, if i remember correctly the ternetzi and common red belly are technically the same fish. so why wouldn't they be able to cross breed? does anyone know the scientific reason?

also, if piranhas [and other fish] are not sexually dimorphic, then how do they distinguish the sexes at breeding time? scents maybe?


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## rchan11 (May 6, 2004)

Better have Frank answer this one because I don't have the foggiest idea.


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## moeplz (Feb 21, 2005)

i dont think that its they cant i think its just they dont. not sure.


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## hastatus (Jan 16, 2003)

> hyphen Posted Yesterday, 07:40 PM
> piranhas inter-breed? it doesn't make sense to me. completely different cichlid species can inter breed, but two piranhas can't? i mean, if i remember correctly the ternetzi and common red belly are technically the same fish. so why wouldn't they be able to cross breed? does anyone know the scientific reason?
> 
> also, if piranhas [and other fish] are not sexually dimorphic, then how do they distinguish the sexes at breeding time? scents maybe?


The answer is simple but yet complex. Cichlids are predisposed to interbreed. Characins are not. That's why you have such problems of Angelfish and ram's interbreeding. The genetics are more closely tied to each other than characins are.

Under the science of phylogenetics hybreds are "rare" and not always found in nature. As for "how do they mate" which is actually your question, pheronomes are released that tell the potential mate its time. Just like a black widow spider knows its time to allow the male to approach. But watch out of things don't go right!


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## hyphen (Apr 4, 2004)

iiinteresting. but from the looks of it, all members of the pygocentrous species look pretty similar in regards to genetics. i know it's not all looks, but it is a big part. i mean, some cichlids don't even look remotely similar. so what you're saying is that it's simply how the dice were rolled? genetic predisposition towards interbreeding?


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## hastatus (Jan 16, 2003)

Yes, and though pygocentrus species look similar, they are landlocked away from each other so their genes are NOT predisposed to mix.


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## hyphen (Apr 4, 2004)

thats interesting. what a weird world we live in...


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## hastatus (Jan 16, 2003)

> hyphen Posted Today, 01:01 AM
> thats interesting. what a weird world we live in...


Just people are weird. You can tell by the oddities that are human engineered in the lab. The flowerhorn is a good example. Even the governmental DNR are still trying to create the perfect trout in the lab fooling around with genes.


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