When I first found these tiny dendronotus, I was certain they were Bushy-backed Dendronotus or Dendronotus frondosus, but the inaturalist community quickly corrected my error, pointing out that D. frondosis is a separate species,  now limited to the Northern Atlantic.   There seems to be so little information about this newly designated species that I cannot determine its maximum size. The individuals documented here were between 10 and 20mm.   I first discovered these beautiful little dendronotus while kayaking alongside a dock. Every spring I now look for them in floating sargassum and bushy hydroids (their prey). They can vary in colour from light yellowish/white to deep brownish/red to bright pink.