ok. well its very hard to determine the "correct amount" to feed him lol. ive gotten mixed messages the dude who sold me the fish said feed him 20 pellets twice a day. But i feed him the medium sized ones. so far ive been feeding him 20 a day, once a day cause i thought u dont need to feed them twice a day. But he hasn't really grown so idk.. Is there a rule of thumb or something to determine how to feed a flowerhorn? also, when cleaning out the carbon, do i throw out the old carbon or leave it in there and dump in the new carbon?