Two days ago I found one of my Black Widow Tetra firmly wedged in a cleft in a piece of bark log. I've no idea how long he'd been like that but I think he'd gone in after some food that was trapped in there. After a while I managed to free him and he swam away flipping onto his side and having difficulty orientating himself. Then he kept finding hiding places, and would reappear occasionally, swimming normally for a few seconds before rolling over. Latterly he's just hid away in his cave either on his tail with his head up or on his side. Everytime I think he's dead and investigate, he makes a valiant effort to swim for a while. He is able to stay upright for a few seconds Last night I thought the other fish were showing too much interest in him and noticed part of his tail fin was missing so I've put him in a breeding net box for protection. He ate something this morning but most of the time he's lying on his side. I'd hoped that given time to rest and recover from his ordeal he might be able to stabilise himself in the water, but it's not looking hopeful now and I'm not sure how long I should let this go on now. Any advice would be helpful.