I am watching a betta fish for my daughter so I don't know if this is a change in her fish or not (she's unreachable in Kenya). The tank is 10 gallons and all the parameters are fine; she explained all of that before she left.
He seems fine except that I can see the red of his gills, which might be normal. The weird thing, though, is that he sometimes flares out one gill. I don't know if this is different behavior for him or not, but I was thinking it should be symmetrical. I'm worried it's gill disease so I've started Maracyn Two. But I just don't know for sure, because he seems absolutely fine in all other respects -- eating fine, very active, telling me who's boss when I put the Maracyn Two in the tank.
I don't want to keep doing the Maracyn Two if it's very unlikely to be gill disease. But from everything I've read online, gill disease is very bad, so I don't want to overlook it or respond too late.
My daughter told me to post here if I was worried.