Radianthus malu occurs in scattered areas ranging from Japan in the north, to Australia in the south, east to the islands of
Hawaii and west to
Sumatra. The only anemonefish associated with this species is
Clark's anemonefish (
Amphiprion clarkii). Sexually mature fish are rarely associated with
R. malu, however the reason for this is unknown. The relationship between anemonefish and their host sea anemones is highly
nested in structure. The anemonefish is the active partner in establishing the interaction. As the single hosted anemonefish,
A. clarkii, is the extreme generalist, it may be that
R. malu is a marginal host tolerated only by the least selective fish and only when no other host is available. ==References==