Goniobranchus fidelis can reach more than 25 mm (0.98 in) in length.[5] The foot of the animal is cream in color; it is elongate and is almost covered by the edges of the wide mantle. The more central part of the mantle has a creamy-white area with scalloped edges, whereas the entire wide margin of the mantle is orange or red. Where the two differently coloured areas meet, there is a burgundy-colored border which varies in width from one animal to the other. [6]
The rhinophores are laminated, contractile and greyish in color with lighter colour at the tip. The shade of grey varies from one individual to another.
The gills are the same colour as the rhinophores and they are retractable.[7][8]
Distribution and habitat
This species was described from Sri Lanka, Indian Ocean. The distribution of Goniobranchus fidelis includes the tropical Indo-West Pacific and Red Sea.[5][9]
Its habitat is the external reef area as well on the top or on the slope up to 20 m (66 ft) deep with a preference for dead corals.[10]
Biology
This sea slug is benthic and diurnal, moves without any fear of being taken for a prey, because of the presence of defensive glands distributed in its body tissues and shown to the potential predators through its warning coloration.
^Debelius, H. & Kuiter, R.H. (2007) Nudibranchs of the world. ConchBooks, Frankfurt, 360 pp. ISBN978-3-939767-06-0 page(s): 150
^Gosliner, T.M., Behrens, D.W. & Valdés, Á. (2008) Indo-Pacific Nudibranchs and seaslugs. A field guide to the world's most diverse fauna. Sea Challengers Natural History Books, Washington, 426 pp. page(s): 217
^Rudman W.B. & Darvell B.W. (1990) Opisthobranch molluscs of Hong Kong: Part 1. Goniodorididae, Onchidorididae, Triophidae, Gymnodorididae, Chromodorididae (Nudibranchia). Asian Marine Biology 7: 31-79. page(s): 58
