Sand sifter

[Black Phantom]

My sifter is two years in my tank and seems to have done very well for himself. My sand bed is quite deep as well so I'm sure he has plenty to eat. I don't think I would go any smaller then a 77.
You will want to make sure that your tank is well established so he has a good food source. You should be able to see a lot of worms and such up against the glass. They won't eat anything but live food.
Hope this helps