I've noticed the past couple of days off and on 1 of my tiger barbs will float in the same spot always face down and other times he'll swim around normally. Does anybody know why he's doing this or if it's normal for tiger barbs? Recently my dwarf gourami had fungus the night I brought him home so I'm positive he had it before I got him. I removed him from the tank and treated the main tank with fungus guard and all the other fish are doing fine, is it perhaps caused from this?
Check your nitrite. Headstanding is a common symptom of nitrite poisoning in barbs. I suspect it's probably fine if the other tigers are all okay, but it's worth checking. If it is fine, then that fish is probably sick with something else.