So, today I brought home Cryo, a potentially-stunning peacock-colored betta fish, couple years old. My friend's brother got him as a surprise gift and had only been taking minimal care of him, so when I volunteered, the brother gave him to me. Cryo is a Delta-Tail or possibly a Half-Moon. I can't say for sure as his fins are quite damaged and he won't spread them.
Cryo's fins looked ripped or split for the most part. We're talking very long cuts, though not as far as the base. One follows the natural line of the fins, the other crosses over a few sections, leading me to believe he tore them on the pretty, but very cruel plastic plants that had been in the tank. His top fin is oddly withered, like it's cringing. It doesn't look quite right. No signs of actual fin rot, though- no discoloring and no jagged edges.
Behavior: He's still eating. I fed him some bloodworms and he was delighted. But for the most part he just sits and breathes, he doesn't really swim much. He's also extremely non-aggressive. I had nowhere to put him while I fixed up his tank, so I set him in the goldfish tank with a QT net. He seemed mildly interested, but not really concerned. And then I tried getting him to flare at a mirror, and he actually ran away from himself.
He lives in a 2.5g acrylic tank, filtered appropriately. He seems to perk up a bit after water changes, and I always use conditioner. I've had him just a few hours now. What can I do to help his recovery?