So my lil 6lb RES Joe has lost his former appetite. He has had to live in our house the last year while we renovate, I bought him a heater for his water since there currently isn't heat in our house. There are times when it's loud in the house banging & such, but my hubby has insulated his room, & he lived in my bedroom as a rebellious punky teen so I know he heard loud music/movies... And he often slows down around wintertime, not pooping/eating much... But lately I can't get him to eat

its been a couple weeks & he'll take a couple bites but hardly anything... he doesn't want my celery stalks, pellets he recently made me switch to turtle pellets after 10 years of being happy with koi pellets.. He was getting fish for awhile a yr ago but they made him aggressive & after 15 peaceful years he snapped at me so I really dont want to go back to those... The temp was cold for awhile when his heater shorted out (and eventually blew up taking out a chunk of my 50gallon tank

) so could the cold be the culprit? He had a small spot of white above his eye that I'm watching, pretty sure from not wanting to get out of his nice warm water... Would not basking slow his metabolism?? Tips greatly appreciated, he's been my sidekick for a long time now, don't want to over or under react..