It's your choice, they can live fine with that curve but in a community they can easily get outcompeted for food. I had a Tiger Barb with a crooked spine, after weeks of debating with myself I finally did it. He was feeding fine but it seemed like a struggle. It was a hard choice and I wish you luck with whatever you choose.
I was told by my lfs that it can be passed on. Therefor, if you are intending on breeding, you would want to. If not, they can live as long as you make sure the other fish in your community aren't getting all of the food.
When I was first starting out with fish I had a couple of guppies that developed curved spines. Despite them swimming and eating fine I doctor googled myself into a paranoid frenzy thinking they had fish tb and euthanized them on the reasoning that it was highly contagious and ultimately fatal and could potentially spread to the whole tank. Lesson - dont doctor google. Observe. Most guppies with a curved spine are generally fine and will live longer and it's often a marker of old age.
I have a cherry barb called Hunchback Red. He has a curve in his spine and he's still alive and well. If your fish is showing no other signs of illness like tuberculosis and doesn't have trouble swimming, I don't think you should euthanize.
As long as it seems to be that one fish, and you're not into breeding, and the fish seems happy enough, I wouldn't. If the fish has always been like that, then I am reminded of a partially paralyzed bunny I took to the vet to be euthanized. He was like, was he born that way? yeah... He eating okay? yes.... Well he doesn't appear to be in pain, he's eating, he has nothing else to compare his life to, so why do you want to put him down? well, put that way...
Not that I was eager to, I just was concerned that it might be suffering. Point is the fish isn't going to understand it's deformed and unless it seems to be in pain, that's all the life it knows.