Depending on the size of the tank and inhabitants, I use a variety of dithers, including redtail brycon (Brycon sp.), black-barred silver dollars (Myleus schomburgki), silver tetras (Tetragonopterus argenteus), African redeye tetras (Brycinus longipinnis), and various rainbowfish species such as Irian reds (Glossolepis incisus), Boesman's (Melanotaenia boesmani) and parkinsoni (M. parkinsoni).