columbian sharks worked in my first african tank. My wife wanted him so I tried one with my africans. It ended up being a mistake as it will be a mistake with a blackfin shark. These catfish get way to big and command way to much of an appetite. Catfish turn into menaces at bigger sizes when feeding time comes and suck up food fairly fast and wont stop. I moved my wifes columbian (which turned out to be a non stop tweaking fish that dosen't even sleep by nature) to its own 50 gal brackish tank and i'm constantly moping and refilling water that it kicks out on daily basis it's now about a foot in length. Very pretty but annoying fish. My friend has a big tank that stands pretty tall. He has a foot long blackfin with some GT's and JD's. Since these cichlids stick closer to the bottom and didn't want a foot long catfish in their territory, the blackfin just swims around the top of the tank never really attempting to graze the bottom. Just my experiences, some may work may not. I know with most africans syodontis will work unless you plan on breeding then IMO NO catfish is advisable.
