Swordtail bent spine

[Salty&Onion]

Seriously, I dont know if he’s a male or female cause he’s always fighting and fin nipping and never pregnant.

Does he have a gonopodium or a triangle anal fin?

 

[Colin_T]

Seriously, I dont know if he’s a male or female cause he’s always fighting and fin nipping and never pregnant.

It's female but won't have babies if it has a tumour or something else growing in it.

Basically, the fish is dying and you should just look after it until it stops feeding or has trouble swimming, then euthanise it.