Yes, AG gives crayfish a good scrubbing. With an unused toothbrush in hand, AG gently scrubs the crayfish with first the water in their respective tanks, then rinses the crayfish with new water, and then scrubs again. The water is then changed. The toothbrush acts like a little loofah. The reason he does this is to prevent shell infections and crayfish plague, which is a shell disease.
It seems to work, although the crayfish don’t like it, much like when you give a cat or a dog a bath. They pinch the toothbrush quite often. Our biggest kahuna, seen above, even grabbed a nearby sharpie in protest. Maybe he thought it was eyeliner?