I work in the lfs, and in the few tanks that have sand we do get gas build-ups, and i have seen catfish - corys, plecs, any catfish in there - unearth this and get a shock, plus the gas is usually a nitrate derogative (mainly harmful gases) that do not help the generall fish health. Plus you have to dredge the bottem of the tank, you cannot sigphon it cos you lose the sand. If you have a powerful filter system the sand gets disturbed and you could find that some plants get buried or there are sandbanks building up in certain areas.
If you are prepared to deal with the problems sand gives, then it is good and all bottom feeders like it, so long as there are smooth rocks in the tank. If you just want to be different then my advice would be to have a graveled tank, with perhaps one corner or patch of sand.
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