Aggressive molly

Question
Hi Richard, I have a 20 gallon tank with 1 Male black molly, 1 female black molly and 1 Lyretail male molly along with a few tetras. The lyretail molly is aggressive towards the male black molly, keeps chasing him all over the tank. I bought an isolating net and gave the male lyretail molly a time out (no food for 2 days). After 2 days, I gave him some food and re-introduced him to the tank. As soon as he got back, he started chasing the black male molly again. I got 2 female lyretail mollies in order to calm him down, no luck. The male lyretail molly has already killed 2 male black mollies in the last 2 months. How can I keep the lyretail molly from chasing and killing other male mollies? He absolutely shows no interest in other female mollies.

Answer
Hi Darshan

All male Mollies in my observance of keeping them, have been aggressors toward other male Mollies, as well as other small fish. Male Mollies should be solo in a tank with other females. This applies to all male Mollies whether Lyretail, Dalmatian, Black, Gold or what have you. Sometimes, I've really had no choice but to put more than one male Molly together, but they have been Black Mollies. What I have noticed, is sometimes it actually isn't aggression, but rather a playful game of chase. If my Mollies are just chasing each other but not fighting with physical contact, or upsetting others in the tank, I generally leave them be. You really shouldn't punish them for doing what comes naturally to them.

If the Lyretail is killing the others, this isn't just a playful chase and he needs to be removed from the tank and not put with other male Mollies. You should start another tank with him and the females that you bought. But not put him with any other male Mollies, or smaller fish. Make sure to put him with fish of similar or larger size, like Tiger Barbs, Gouramis, medium sized Angels etc. If any of my Mollies killed another fish, I would take him out and put him in with some larger Cichlids who would make sure he behaves himself. But don't make them go without food :-(


I hope this has been helpful to you, good luck!

Richard