I currently have a very nice male in a filtered, heated 5 gallon tank and would like to try and breed him with a nice female. I bought 2 females and stuck them in my community tank to fatten them up. The tank is 4 feet long with lots of hiding places. The tankmates were 14 Glow-fish, 5 Red Eyed Tetras, 3 Serpae Tetras, 4 Glowlight Tetras, a tiny Cory Catfish, and a very peaceful Red Tailed Shark - the most peaceful one I have ever seen.
I introduced the 2 female Bettas and watched them carefully for a few days. As expected, they weren't crazy about each other but could easily avoid contact and did. Nothing else in the tank showed any interest in the Bettas more than a curious look. The Red Tailed Shark, my greatest concern, could have cared less about them. Everything went well for a few days.
Today, a week later, I came home and one of the Bettas was beaten nearly to death. Half her fins were missing and she was barely making it, but she did come up and eat some food. I couldn't find the other one for love or money. I finally began pulling up decorations one by one till she fell out of a ceramic head mauled and dead as a hammer.
I looked closely at all the fish and these were the only two to have been ravaged. Did they fight to the death? It would certainly appear they did, but I thought females would just form a pecking order and not out-and-out try to kill each other, especially if they had plenty of room to avoid contact and this was certainly the case. Or did something else in the tank single them out and attack them? I really don't think so, but I guess it is possible. Maybe the shark - I know they are prone to acts of aggression but I have never before seen him act the least bit mean towards anything. Maybe the Serpaes - they are sometimes known to nip fins, but never like this that I have seen. The Red Eyed Tetras are just a bunch of wimps, so I don't think they had a thing to do with it. Certainly not any of the Glow-fish. They are tiny and harmless, or so I thought. Could they have done this? Any thoughts?
I moved the living Betta to her own filtered and heated 5 gallon tank to recover and will probably leave her there permanently. I like female Bettas though and would like to keep a few around, so I am curious to know what others think happened. Are female Bettas getting meaner? Decades ago I used to have no trouble keeping several females together in decent sized community tanks, but maybe they are just too mean these days to keep together at all. Or does anyone think their tankmates did it?