[My tank is very lightly stocked with no alge problems but there is the normal funk in the bottom. I am worried that I need to give them some food but I am unsure of what kind. TIA for any advise. George] said:[The whole point of the snails and crabs is to keep your tank clean. If you have to add more algae to keep them fed, you are pretty much shooting yourself in the foot.
The stuff that forms on the glass and rockwork will keep your critters fed. As long as they are hungry, they'll keep the tank clean. Avoid overfeeding if possible.
If this is an empty unstocked tank, you might add a pinch of flakefood once every five days.]