Can't say I agree with the above poster... But I would def give the fish time to heal. It's has a good shot at recovering. If it takes a turn for the worse or starts to refuse food for more 'n a day or 2.. def worth reevaluating... But putting an animal out of it's misery is the most UNSELFISH thing an owner can do for it. working in the pet trade I see people with animals that are in constant pain and have no quality of life... but the owner feels to bad.. to put the animal down. It is selfish, and only self serving. It can be a hard call to make.. but ultimately only you can make the call.
One of my own gar recently had a similar incident.. he did not have any physical warping of his spine but was acting odd and swimming funny ( concluded he prolly gave himself a good one and it was spinal damage) Took him a few weeks to recover but he is now fine, and will hopefully live out a long life. Even if the back itself doesn't straighten back out if he is swimming and eating and otherwise recovers I see no reason in putting him down because he may "look funny"
Good luck, and hopefully you will have a very positive outcome.
Guess I'm a murderer then, as i kill gars with broken backs.
They have true spines of bone unlike modern fish. Imagine if you had a broken back and no painkillers or anesthetics to help you deal with it. Now imagine that whenever you try to eat your entire body goes into violent spasms and twitches because your jaw is connected to your severed spine.
If it does not heal or the fish is having trouble swimming or eating, euthanizing is the best option.
My decision, from reading about some gars recovering is to hold off for a couple more weeks abd see wut happens. He is still eating and acting the same way he was. If no improvements r made then u will be able to call me a "murderer". Like mike said, gars backs are like ours. There's no way he's not in pain.