when I first started my aquarium i had 3 black mollies (55gal tank) and i got males cause i don't want to deal with the breeding issues. the all died so i took them back to the store and got 3 more black mollies but i forgot to tell them all male so I think i ended up with 1 female. the 2 that were males died about 2 weeks later, she lived a little while longer but died after doing a water change but i think she was sick. i had 6 tiger barbs and had 2 in that group that fought all the time. one died, so that left me with 5 and since then 2 more have died. so down to 3 and they don't fight, they don't nip anyone. They do their own thing. I like them but I didn't care much for the molly after i got them. I will say this for the molly...the female was curious....trying to do a water change and she acted like she wanted to help.....