I put 2 more liters in today so the glass part of the thermometer is covered im leaving a couple inches at the top since I'll be adding some decor soon and maybe another plant so I don't want the tank overflowing when I reach down. The corys are so happy! They went to eachother almost instantly and rarely leave eachother. I did buy an outside sticker thermometer because i'm a bit paranoid with glass inside the tank (if it shattered or a fish hit it, that'd be awful). So the readings say its between 78-82 I believe. The thermometer was already on asetting before so I know how much to turn it up to get the temperature they had in last tank. I think what I will do is take back the 2 bigger fish (the diamond shaped ones ) since they kind of bully the other fish (especially the new corys.) plus my teacher said he'd like a couple of more, but I'll be keeping the others. That will bring my tank size down to 12, so I think thats going to be better. my biggest fear now is making sure the ammonia levels stay safe.