How long is the quarantine, and what temperature is he in at the moment?
(not nagging, just asking :) because at this time of year, my betta definitely need a heater)
You must be a fair bit north of us! We're still getting temps in the mid 90*s. Water is a comfy 78*-80*
He's in quarantine for four weeks, mostly because I have no idea how he was kept and if he's got any sneaky parasites. Have to be careful, since he's going in the big planted tank- it's impossible to medicate. Yes, will hopefully be moving him to a bigger quarantine tank soon!