Meridian Adventure Dive bring you the monthly Raja Ampat Creature Feature series: Gloomy Nudibranch
Nudibranchs, often sea slugs, are fascinating marine gastropod molluscs known for their vibrant colours and intricate patterns. They belong to the order Nudibranchia, a diverse group comprising thousands of species. These creatures are found in oceans worldwide, from shallow tidal pools to the depths of the abyss.

Nudibranchs are renowned for their remarkable defence mechanisms and feeding habits. Many species incorporate toxins from their prey into their tissues, making them distasteful or toxic to potential predators. Their bright colours often serve as a warning to predators to steer clear.
Their diet varies greatly depending on the species, but they commonly feed on sponges, hydroids, algae, and sometimes other nudibranchs. Some nudibranchs have evolved fascinating adaptations, such as stealing chloroplasts from their food sources and using them to perform photosynthesis, known as kleptoplasty.
Overall, nudibranchs are visually stunning and play significant roles in marine ecosystems, contributing to biodiversity and serving as indicators of environmental health.
The Gloomy Nudibranch, scientifically known as Tambja Morosa, is a species of sea slug belonging to the Nudibranchia order. These striking creatures are renowned for their vibrant colours and unique patterns, which serve as a defence against predators.
Tambja Morosa typically measures around 5 centimetres in length and can be found in the western Pacific Ocean, particularly around the coasts of Indonesia, Japan and Australia. They inhabit rocky reefs and are often found in shallow waters.
One of the most distinctive features of the Gloomy Nudibranch is its deep purple or blue-black body adorned with bright yellow or orange spots. This colouration warns potential predators that it is toxic and should be avoided. Like many other nudibranchs, Tambja Morosa obtains its toxicity from its prey, such as sponges and tunicates.
Despite their small size, Gloomy Nudibranchs play an essential role in marine ecosystems. They help control the populations of their prey species and contribute to the overall biodiversity of their habitats. Their stunning appearance also makes them popular subjects for underwater photographers and divers.
Situated in Raja Ampat, Indonesia, Meridian Adventure Dive is a PADI 5 Star Resort and winner of the PADI Green Star award. Scuba divers enjoy our professional services that have become synonymous with both the PADI and Meridian Adventure names.