hehehe ... crayfish still around .. kinda too big to fit into the aro's mouth. It did try but the crayfish flashed its claws and the aro just backed off. It found a place to hide, below the round stones at the middle of the tank. Crayfish doing a good job cleaning up the leftovers that fell to the bottom.
I only clean the gravel once a year. What I do is that I will remove all the rocks, plants and decos.
Cut a 1.5lt PET bottle into 2 and connect the upper half to a water hose and use it as a gravel cleaner. It will suck up all the dirt.
It is important that you maintain the good bacteria colony in your tank so that cleaning will not be so hectic. It maintains the water quality too.