Guppy's fin stuck?

Question

My guppy has such a narrow fin I think it's called fin clamp why is that and how can I solve the problem regards, Alex

eieiei2 · Answer

Fin clamps are usually an indication of an infectious disease.

It can help to reduce the germ pressure in the water, so the number of germs floating around per liter. For this you have to do a lot, best for a few days a day, water change. Line water is almost germ-free. This relieves the immune system.