i have no clue what happened two days ago i had to clean my betta bowl so i put the betta in the communitiy tank (he was floating in a net so he would not attack anyone)but when i came back to put him back in his bowl he was gone! i searched the tank to find out that he had escaped and surprisingly happy and calm even with his mate in there the next day i went to check on him and found him at the bottom of the tank hiding under a rock with his fins in shreds, i figured the danios had ganged up on him so i put him back in his bowl and since the he just sits on the bottom and hes the only fish in there. he is three years old so im not sure if hes just reached the end or there is something wrong please help me.