Goldfish fry

[Kyshiara]

Hello! I have around 30 goldfish fry, and I am worried about one of them. Do you think it has a bent back? And if so, is there anything I can do for it? It's parents are a common orange male X a sarasa comet female.

Also attached is a picture of his quarantine tub.

Thank you!

 

[Kyshiara]

I should also mention that I have been giving it salt in very small doses, because I though to start with it was a swim bladder issue. I was also giving it Esha 2000 for a short while but I stopped when I realised there was no point.