Any turtle head that is small enough to fit into any alligator snapper's mouth will probably get chomped on. Or, I guess the way to look at it as that once your alligator snapper's mouth is large enough to fit any of your other turtles' heads in it, you might want to keep 'em in different tanks. I've never had a problem keeping two hatchling or yearling alligator snappers together. I just never had any other turtles with them. John Richards once told me about how he lost a painted turtle to one of his ally snappers. I think all of the turtles involved were hatchlings.
:Does anyone know what age or size alligator snappers start preying on other turtles? Thanks,Steve