Originally Posted by ophiura
Ophiura Is correct as to the sand bed.
My choice too if it has to be a fish would a Diamond Goby (aka) Rotor-tiller fish) if you want to have spotless substrate. But they have many downfalls too.
The issues with them are they tend to be jumpers ( no issues with mine) quiet home no kids anymore to startle him with noise. Also a nearly 50 gallon fuge feeding the little pod eater. I have seen where they are tide poll skippers. As long as they have food in this "little tide pool" I think they do not tend to try to leave the pool (jump out of your tank) But it your tank runs out of pods etc , carpet surfing 101 seems to be their next class in school.
The do eat just about anything in the substrate (pods included) leaving the substrate barren of seeable critters. Next, they will rearrange the landscaping of your substrate regularly!! If you have a "DSB" he will make mountains out of it in places. Other than these issues, they are just about unbeatable at keeping the substrate clean, but you pay the cost of living with these issues forever more. Plus they are a neat fish to watch work......... Good Luck.... Warren