they have little white deposits kind of like urates in snakes. i keep mine in 5 and 10 gal. tanks. i completely clean out tanks 3 or 4 times a year., spot clean when needed. they aren't really messy, i only feed once a week. when doing tank maintenence i use a 2 liter bottle to catch the tarantulas. cut the bottom out of it, use it like a funnel to catch the tarantula then use a flat piece of cardboard or something similiar to cover the bottom up. you can tape the cardboard to the bottle to keep the tarantula in there while you clean. if you are wondering i don't do this for rose hairs or pink toes, i just hold them. this method is for the goliath birdeater,columbian blue bloom,indian ornamental, and the columbian red leg all are aggressive.

thanks

vaughn