You have made some good points here, thank you. I assumed they were the same mites as the snake mites would be. I never considered that it could be a different type of mite. All I know is that it was very small, and black, floating in the water. I had to strain my eyes to see if it was dead, which I believe it was.. I will most certainly change my arrangements then! I ought to have let the shop know. They've been great in every other respect. I had my snakes from them too.