I just got a new 5 gallon tank for my betta, Fish. I put him in yesterday and this morning he was belly up (yikes!) however, i put him in his old bowl,with his old water and no filter, and he seemed fine when i got home from work at 4. i put him back into the tank and he swam around for a while and seemed fine. However, an hour and a half later, now he does not seem fine. He stays on the top of the tank and floats. He lays against the filter and does not be able to swim on his own. he doesnt do it often, but when he tries to swim down he ends up floating back up to the top. he seems very lethargic. i dont think it is from amonia because i took the water to the petstore and they said the water was perfect. is this because of the current from the filter? my cories seem fine. I dont understand what is wrong with my beloved Fish, and this is really scary. i need help!