Good dither fish

[TheOscarFishKing]

Hello have have three oscars and five black belts and I know that the black belts when they get older can kill my oscars. Right now those are the dithers. Could I possibly get a few medium jack dempseys and use those. Maybe a few green terrors as well

 

[J. H.]

Do rainbows or barbs. Why do you want to add another type of competition/ aggression/ general cichlid garbage to your tank? SDs are cool too.