I've seen it go both ways.

I hope it passes or doesn't cause problems with your little guy. Can you remove the rest of the gravel? I feel like this happens more with captive bred fish.
I also agree with
twentyleagues
that it looks like you have two senegals - one albino, one regular. Not a palmas.
I'm not an expert on water changes, but doing 1 gallon 3x/day seems like it would possibly be stressful for the fish. A single 3 gallon WC might cause less stress. Just a thought.
Also not sure if you should hold water changes if you dose espom? Maybe
kno4te
can speak to that?
Good luck! We all know how these bichirs can worm their way into your heart.