Okay, so I shall start with my Betta seems strange the last few days, and its probably nothing. It all started, because I have two betas in a 10gal, one baby one adult, i noticed the adult has been getting angrier lately as the baby is growing his fins and ended up attacking my tetras. Moved the baby to my 16gal and all went back to normal. Then I did my regular 30% water change about 3 days ago, noticed it kicked up a lot of excess junk in the water and he also seemed really irritated, rubbing himself on things again. After two days, today hes been cool beans and gravy. Today, I got 15 new tetras, added 5 (making 12 total) tetras to his tank, and replaced the filter cartridge which kicked up excess junk in the water from the old cartridge. Now he's laying himself against the barrel I have in there, seems to just be this general area that hes doing it. Prior to this (last night particularly) I've seen him getting stuck to the filter intake, which has always been a problem with other fish, is this behavior anything to worry about? The tank remains relatively clean, even when I do changes its only ever got a little debris. And about 2 months ago I treated all my fish for a fungal infection(because of two new tank mates) and havent noticed any other issues since. Should I be worried at all? I use a betta water dechlorinator, api stress coat and api ph down in the water so everything should be relatively normal at this point. I do have a heater that keeps the tank just under 70. While we're on the subject, my 16gal has an aqueon heater that immediately built up some kind of white stuff on itself after I got it what is this from?