"This is an interesting photo that I am pretty sure the individual is Hypselodoris infucata based on mantle, rhinophoral, and gill coloration. The only inconsistency is the two front gills which seem to be triangular (normally all the gills in Hypselodoris infucata are diamond-shaped, in contrast to Hypselodoris kanga where all are triangular). However, this apparent triangular shape in just these two gills may be an artefact of the way these gills are positioned in the photo. It would be nice to see another photo of this individual from a different angle.
Having said that, I must add that Debelius & Kuiter have clearly got some identifications wrong for this species group in Nudibranchs of the World and all the species (Hypselodoris infucata, Hypselodoris obscura, Hypselodoris saintvincentius, Hypselodoris festiva, Hypselodoris kanga) are nowhere nearly as sharply delimited as they make out (in other words there is much greater intraspecific variation in colour pattern than this text would suggest), so it is not an infallible reference source. In particular, on page 127 the centre left photo shows an individual in the act of feeding from Bali that is Hypselodoris kanga and not Hypselodoris infucata.
Previous comment from Dr. Richard Willan: A juvenile individual."