I always have fresh,clean water available in Donatello's tank at all times. But this morning, during his bath I noticed him drink a large amount of the bath water. Normally he opens his mouth wide like he's going to take a bite of water but today instead he kinda kept his his mouth closed n it looked almost as tho he was trying to inhale it through his nose lol. But he put his head up ever few minutes to breathe but then went back to drinking, he did this for about 10 minutes. Sorry if I sound paranoid or stupid. Is this normal,or am I doing something wrong?