LOL got images of a poor fish with mop and bucket, while you sit in your armchair, in a smoking jacket, with port and a pie, laughing....
Anyway, nothing wrong with selecting a fish for a purpose, i know what you mean by 'cleaning'. Bristlenoses are good for algai and food detritus. Have you checked out malaysian trumpet snails though? If you want a clean up crew its hard to beat 'em!