Originally Posted by indjo
First off, you need to improve your water quality. Notice the later picture of the male - his fins are no longer straight. This is due water quality.
I suggest you breed him to the PK.
1. Though she is DeT too, PK is believed can improve ray size - your male has rather thin rays. IMO if you can find another female with thicker rays, that would be better.
2. She has nice overall form and color, thus you only need to concentrate on fin length and thickness.
BTW, it's easier to make longer fins compared to widen spread.
There are many reasons why the rays will bend and curve. It could be because of all the plants, even the gravel plays a part. The plants in her tank would make for a wonderful water quality. I believe that the only way for bettas to have and keep perfectly straight fins is to have them in the glass tanks with nothing else in them, just like you see on AquaBid.