Male Betta + Female Betta?
So I got a new tank, and my girlfriend got a new Betta for herself that happen to be a very beautiful Dark blue/black crown tail female. After I set up my tank and before I moved Delta into his new home, she decided to do a WC for her tank. filter wasn't put back together properly so her tank got filled with a bunch of crap, 100% WC. So I said it was ok for her to put her fish into my tank while she did that, before I moved Delta in. She did the water change.
While I got all her fish out. Thinking her Betta was still in it's cup, I didn't happen to take it out of my tank before I put Delta, considering it was hiding when I got all the other fish. I happened to notice that the other Betta was in my tank while walking to the bathroom and noticed Delta acting different. I went to the tank right after I finished. This is when I realized that the two fish had been in the same tank for about 2 hours. I didn't see them fighting but I saw minor aggression (one would chase the other really fast) then they would go back to playing with each other and on their own. Then repeat.
I watched for about an hour, no fin nipping occurred just those same things over and over. I don't know if Delta doesn't mind her being in the same tank as he is, he doesn't show signs of wanting to mate, but more just to play. She doesn't seem to show any hostility at Delta. I'm just wondering if I leave them in the same tank for a while if I would end up with a dead fish, or my girlfriend would end up with a dead fish. My girlfriend insisted on leaving them together but I don't really know.