A couple days ago I noticed my betta acing really strange. He wouldn't swim unless you tapped the glass, hardly ate, & turned colors. I did an 100% water change & placed him in the water. He still didn't swim much but he changed back to his normal blue color. I didn't feed him for a day. Today when I left for work (9am) he seemed as normal as before. However when I got home (9pm) I noticed he turned into a red/brown color. His fins seem pinned down. He swims every so often but only to the top. He's currently laying on his side. I took his heater out (The guy at PetSmart said since its summer he didn't need one as long as his water temp was 80+). I just put his heater back in his tank. He laid by it for a couple minutes. I just don't know what else I can do.