I can’t get a good picture but for a couple of weeks now my betta is keeping his ventral fins clamped. I’m thinking maybe it was because my African dwarf frogs might have started fin nipping, but it looks like where the fins meet the body they are turning a white or a light blue. Just a tiny line on each one, no noticeable other color changes. (Although he is a Koi betta so color changes are a little hard to spot, but looking the same as early pictures)

It’s the only place the color is showing so I’m hoping it’s not fin rot. it doesn’t look like the pictures I’ve seen of it.

Anyone have any ideas?

[he’s kept in a 10gal tank, live plants, 79 degrees, water levels at 0 ammonia, 0 nitrites, between 5-10ppm nitrates, with some shrimp and 2 small African dwarf frogs]