He is housed alone with a few cherry shrimps. Built in filter, nano cube. Nothing sharp, just a few potted nana and a small driftwood with nana, not sharp.
Sometimes they get stuck in intake tubes/slots or injured by other fish and develop redness/veins. Should be OK, keep water clean and watch for infection. It can heal but usually leaves some scarring. The cleaner the water, the better chance for a clean heal.
Well that's reassuring, thanks. I'll keep a eye on him. It doesn't look like a bacteria infection? The current is fairly mild but I will add a few more sponges to slow it even more.