gill

Hey guys so ive had my blood parrot for about 3 months now and he is about 3 inches. He has had the black stuff come up on him a lot but i know how to treat him for that. My main concern is his gills. They are super puffed up and there is like a really thin whit layer at the end of the gills...

One side of my gar's gill looks like this. Is that gill curl or damaged gill? It might've damaged itself since the tank at my LFS was pretty small and was pretty crammed.

My flowerhorn fish has developed some kind of boil on its one side of the gill I cannot understand what kind of disease it is. He eats well, does not have any problem like white crap. But since it has developed this boil, he is really getting aggressive for no reason. It also gaps for air not...