Weird Bolivian Ram Behavior

Hello, all! So I have a male Bolivian ram who has been exhibiting weird behavior for the last six months, and I wanted to see if this was something anyone else had experienced.

While he occasionally swims around the full run of his tank, he spends most of his time scooting along the bottom with his fins or using his mouth to bounce off things. All of his fins appear to be in working order, so I'm not sure why he is swimming this way. He also frequently bumps into his decor (driftwood, plants, and smooth river rocks) by accident. I have a second Bolivian ram in another tank, and she doesn't do any of this, so it's not just a species thing.

He doesn't seem to want to eat his earthworm pellets or algae wafers anymore, but he will still chow down on live blackworms if I put an eyedropper right in front of him and let the worms touch his mouth, so he hasn't stopped eating.

At first I thought maybe he had gone blind, but he still reacts to me wiggling my fingers in front of the glass and also to his own reflection. Then I thought it might be some kind of swim bladder issue, but he doesn't seem to be restricted to the bottom of his tank when he feels like moving around. I'm so confused!

Water Parameters:
Ammonia: 0ppm
Nitrites: 0ppm
Nitrates: 5-10ppm
GH: 11
KH: 7

Tankmates: 10 Honeycomb Catfish, 1 Mystery Snail, Pond Snails