ok, so my oscar, jack dempsey, and (maybe a polleni, waiting for a response on FB) need some dithers. the O is 6" the jack is 4-5" and the polleni is 5". what dithers can i get for these dudes? tried BA tetras, they all got ich and died, and so i'm thinking pictus, swordtails, colombian tetras, or tiger barbs? thoughts? thanks!