This small sea star is commonly found on rocks and jetty pylons. It has 5 short arms (or occasionally 4), and often has a colourful starbust pattern. However, it can also be plainly coloured. There are a number of similar species. One of these, the dual-colour Tosia neossia, is only found east of the Coorong and is difficult to distinguish without experience. The others include Tosia magnifica, which unlike T. australis, has more than 6 marginal plates between a pair of arms, and Pentagonaster duebeni, which has longer arms, is only ever one colour (yellowish-orange to red), and has more numerous and rounded marginal plates.