This fighter doesnt swim much...
doesn't feed much, just hangs out under plans and logs...
He looks to be in ok condition.. any thoughts on what might be up??
could be worth treating with anti internal bacteria meds, as loss of appetite, listlessness and emaciation are all listed as symptoms of internal bacteria problems, and he does look kinda thin. and internal bacteria problems can sometimes be totally symptomless, so the fact that he looks well doesn't necessarily mean anything.
also, that looks like a neon tetra in the bottom of the photo. they can be a problem with bettas, due to them being a bit nippy. and what types of livebearers do you have? is it just the platies? or do you have other types too?