A red net over white, shared with several relatives and settled at the mantle edge.
A chromodorid to about 5 cm, opaque white to cream with a network of fine red to pink lines over the back, closing into a dense mesh towards the centre and breaking into separate strokes near the edge. A red band runs inside the mantle margin and the margin itself is white. The gills and rhinophores are white with red edging. Several Goniobranchus carry a version of this netted pattern — Goniobranchus tinctorius is the one most often confused with it, and is larger with a coarser, more purple mesh. At 3 or 4 cm the two overlap enough that a photograph of the mantle edge settles more than a second look does.
Feeds on sponges and holds their compounds in glands around the mantle rim. Often found in pairs by day, sometimes with a flat white spiral of eggs laid beside them on the same sponge. It is not part of a mimicry ring; the netted pattern appears to be a straightforward warning signal repeated across the genus rather than a resemblance to anything else.
Recorded from the shallows to about 25 m on sponge-covered rubble and rock, and rather more a shallow-water animal than most of the genus.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
