I want discuss about my fish

[trilinearmipmap]

If you want tank mates for him (or her) you would need a larger tank, you will want a bigger tank anyways because he will get bigger.

I have never gotten piranhas because looking ahead you are very limited for future tankmate options and will be stuck with the piranha until he dies.

[KennyKen]

i had gourami's in my tank for 2 years with pirahnas. never touched them as long as i had them.

[Ellie_A]

You definitely need to buy a bigger tank and should not be even considering adding more fish until the pirahna has been rehomed.