I have a 30Gal. Initially I had a harem of 1 male and 3 females with a couple otos. The male at first was very territorial chasing the females around all day. I removed the male. Added 8 cardinal dither. No issues, females all schooled together. Reintroduced the male, to my surprise no more aggression. 2 weeks ago noticed a successful spawn with one female. A week later I noticed the second female also with a successful spawn. 3rd female laid eggs but I image she ate them because next day there were no more signs of the eggs. Both groups of fry have been free swimming for about a week now. Removed the dithers. The female that ate her eggs got picked on by the male. Removed her. The male now shows no aggression. The females don't seem to mind having him around but don't let him get too close to the fry. The tank is heavily planted. When should I remove the parents. So far things have gone well as 2 mothers are on opposite sides and can't usually see each other. The few times they have, they do a tail wag and go off on their ways. They do keep the otos away but rarely show any aggression now. I wasn't expecting them to spawn to soon as I've only had them in the tank for about a month.