I'm new to this forum, been keeping fish for about 3 months now. I have a 60 litre tank. This tank contains 3 corys and five tetras. I also have a 12 litre tank where I have one male betta. I went to the pet shop to buy some female bettas for the big tank, I bought three. One was peach, one was red, and the other was what I thought was a female half moon betta, pinky peach, purple and blue. I thought she was very colourful for a female. When I got home and put them into the 60 litre tank i noticed the female half moon is nearly twice the size of the other two, and is very agressive. It flared at the females every time it came near them. I put the "female" into a breeding box now and "she" still flares every time a female comes over. Her gills become quite large when she flares. I think perhaps I have mistakenly bought a male plakat? I cannot make out any white spot on the betta either. I was hoping somebody would be able to help me identify. I'll try and put on some pictures.
Hope somebody can help!