fish off get rid of the pleco hel get to big for ur tank second r u medicating them at all third do a major water change is wat I owuld say and once ur done treating everthing get 1 more danio wait for gunie or buterly for more advies
How big is your tank? It all depends on that.
cory catfish, (but more than 1 hopefully, they like to have a friend or 2) bushynose or bristlenose (I think theyre the same) plecos, ottos, um...that's all I can think of at the moment
Those "suckerbelly" loaches are also called hillstream loaches and are great algae eaters. However, they prefer strong current in the tank, and are really a coldwater fish, so please keep that in mind. Butterfly has some in her tank. She can tell you more. I had one a couple of years ago and they are quite fascinating when you see them, but stay hidden most of the time, at least mine did.