Just looking for some help here. I have a female sorority up for 3 months with 11 betta in a cycled 36 gallon heavily planted tank. They have been fine other than some very minor fin nipping until yesterday where I came home and found 1 dead with all the fins eaten. Water parameters are all good, 0 ammonia, 0 nitrite and 10 nitrate. All girls are eating well and swimming happily with some chasing once in a while. What I need advice on is two of the girls might be male now that I started to do more research but not sure as they both have very obvious ovipositor and don't fight at all. They actually swim together all the time. The other girls are afraid of them and avoid them.
I am not sure if either one kill that one girl as I don't see them going after any girls when I am around and I spend approximately 5 -6 hours watching them each day.
I have temporary remove one of them, the red one (the more agressive one) to a temporary tank and left the other one in the tank for now.
Appreciate if anyone can help me identify if they are female and if I should remove the other one or put the one I remove back int the tank.
I have attached picture of them.
Thank you for reading and advices.