Guppy Laying On Side

[Bluegills]

Helloooo, my guppy got attacked by my siamese fighter. his tail was really small. used to hide down the side of the tank on his own until i put him in a breeding tank so he could heal/eat properly. ive removed the betta from the tank but this guppy is laying on its side and struggling to move... any idea why or what it could be please? if i can save it i obv will but he does look in bad shape.

thanks in advance

 

[OldMan47]

Clean water is the most common cure for almost anything in my tanks Bluegills. If I can replace the water in a tank and keep the resulting water pristine, damaged fish will often recover from some rather severe problems.