how do you distinguish the sex of tetras?

[ICEAL]

how do you distinguish the sex of tetras? any specie petco sells.

[thekoimaiden]

Depends on the species of tetra but for the most part the females will be rounder and slightly larger. Aside from livebearers most fish don't have mandatory sex ratios.

[Sheldon31]

My female has a rounded tummy and she is a few millimetres longer than the males. She also has a slightly crooked red stripe. She's a neon. Are females a little more aggressive too? Well maybe not aggressive per say but are they more dominant? Does that make sense?....

[ICEAL]

are they easy to breed? will they breed if in school?

[thekoimaiden]

Tetra will usually breed if they are kept in good conditions (heavily planted, clean water, soft water, and low pH). You should research the individual species you want to breed, tho. There is a lot of information out there about breeding tetra.