every time they show up on the surface(which is often) your cham will sprint to them and eat them.
chameleons seem to love them just they aren't any thing but shell so they aren't fed a whole lot. i heard the shell is full of tons of calcium so they are good for the chams.
they are used to bring the most stubborn chams into eating.
now for eating fungus you need alot of them to see any decrease quickly. if you add just a few it will take a pretty long time before they eat enough. also you need to add some rotting wood to soil becuase they either eat that or the fungus that causes it to rot im not sure yet. They are a reletive of the crab and acually breath will gill type stuctures so your soil must be damp at all times.
i think thats every thing...