my clown loach in my aquarium is lying on the bottom of my tank (stomach on the bottom) he is alive

and moves if you touch the tank, but other than that he rarely moves, any ideas what is wrong?

Clown loaches, and in fact nearly all members of the family Cobitidae, are known for laying in weird positions. This tends to be more common after they eat a large meal. Loaches also tend to be shy fish, and it is not too uncommon for them to spend most of the day laying in their favorite hiding place. As long as your water quality is good (0 ammonia, 0 nitrites, and under 20 nitrates), and the loach does not appear disoriented when he does swim, he is most likely fine.

Loaches relish small live and frozen foods such as bloodworms. If you want to lure him out of hidng, try putting in some worms or small arthropods, and he should go crazy for them. Also, because most loaches are shoaling fish, they like to be kept in groups.

I take it your fish is a single specimen, which is probably why he is hiding so much. If you get a couple more Clown Loaches, they should become more active. Be warned, however, that this species grows very large (they are a food fish in their native range), and full-grown Clown Loaches need at least a 100 gallon tank. They can be kept in smaller tanks (around 30 gallons), however, for the first few years because they tend to grow slowly. Because of their potential activity level and relatively large waste-output, they should not be kept in tanks under 25 gallons for any length of time.

Hope this helps.