I agree with all the others, hmmm...Rummy Nose I should try them. As maintenance workers to keep the bottom of the tank clean I've always kept Brochis catfish. I think the commonly found ones are the Britski type, also sold as Green Catfish, but I occasionally find the BIG ones, which I think may be Radiatus.
These are excellent worker fish to help keep the tank clean and place no demand on the Discus. They live for many years and tolerate all the conditions that the Discus do well in. In good condition, they are very attractive in their own right with their segmented armor radiating a nice green color. They do well in groups and I can keep as many as 6-10 in a moderately sized tank.
Be careful when netting them as their dorsal, and especially pectoral fins, are very sharp and spiky and usually get snared in any type of net other than the very tightly woven white brine shrimp nets. Untangling them can be difficult and sometimes fatal to the fish. I've accidentally pulled their pectorals and caused fatalities. Better to use the very long handle brine shrimp nets that are also good for reaching the bottom of a high tank for maintenance. Outside of that they are great and generally sell for about $5-$6 each.