One of my 4 dwarf gouramis has been looking sick the last few days. The other 3 all look fine, are swimming well, eating well, and are brightly colored. The sick one looks thin, has trouble swimming or maintaining his depth in the water, has trouble getting to food, and has lost a lot of color. He spends a lot of time resting on the bottom or on plants or hiding. I think he has a problem with his swim bladder.
What can I do to help this little guy?
Could be an internal parasite. I would isolate if hes doing okay and treat him with internal parasite guard or pepso food (becareful using it around inverts though!) Weight loss like that usually has to do with something in the gut.