they are so cool!! mines a good 3 inches too but hes not much of a cleaner more of a predator as i see him with brittle starfish in his mouth a lot, so i got the cleaner shrimp and man it was scary he chased the cleaner all over real sneaky guy too, he kept trying to grab the cleaner with those claws, i was tempted to break off his claws and see what happens but i couldn't bring myself to it. the cleaner is close in size but the tempermant of the coral banded hes just hardass ahhaha, i forgot to mention my tanks a 37g tall i think, so yeah im sure there more room in a 75g but i think its just a matter of time before he catches him.