In a 75 with a rd most fish are going to get murdered to be honest and the species that could stand the rd probably grow far too big or could kill your devil. to keep a 2ft catfish you need at least 3ft width and 6-8 ft tank length.
soribum lima , shovel nose are far too delicate and i wouldnt to subject a tigrinus to a rd anyway cos they are way too expensive.
and the tiger shovelnose get to 4 foot easily, and could eat your devil at that size.
sorry to be negative but most big cichlids make life a misery for catfish companions.