there are no fish that should be subject to 'cleaning up the garbage' as a diet and certainly, chemicals should never be used. yes, there are numerous catfish types that are bottom feeders, but what they're looking for down there on the bottom is nutritous, healthy food .. a few tidbits left over from food that didn't get snatched up immediately by the rest of the fish.
there shouldn't be enough 'garbage' for you to be concerned with beyond a relatively simple gravel vacuum on a weekly basis coupled with your regular weekly water changes. if there is, then you are (a) seriously overfeeding and/or (b) have a seriously overstocked tank.
too much garbage on the bottom is easily fixed. not by putting a bandaid on the problem with chemicals but rather, by preventing it in the first place.
