Rhinopias are a type of scorpionfish, known by many divers as the holy grail. They can only be encountered in certain areas in the Indian and Pacific oceans and dive sites get frequented by divers just because they are known to be there. Here are some fun facts about these amazing creatures, the best destinations for divers to find them and how divers can identify what they find.
Masters of camouflage
Even in areas where Rhinopias are found, divers still need to be lucky to see them.
They are very well camouflaged and they mostly rest on the sea floor, where they blend in with their environment. The most common types live in typical muck diving sites with sand, rubble or rocky sea beds. The eyes of the Rhinopias site high on top of their heads, making them easier to find once divers know what to look for.
Big mouths seize the day
Rhinopias hunt at night and wait, camouflaged, for prey to approach. Opening their mouth wide, they suck the prey in and swallow it whole. They usually feed on smaller fish and invertebrates.
They can walk
Mostly Rhinopias can be seen to “walk” on the bottom using their pelvic and pectoral fins. They could swim, but they rarely do so.
The perfect timing to take a photograph of a Rhinopia is when it is yawning or, in other words, opening their mouth widely. This behaviour can also be observed with other scorpionfish and frogfish and it is done regularly, every half an hour or so. It happens more often when photographers shine lights and flash strobes at them, though we don’t recommend doing this as it can disturb their natural behaviour.
How many species of Rhinopias are there?
There are 6 known species of Rhinopias, whereas only three are usually found by scuba divers. The most commonly seen are the “weedy” and the “paddleflap” Rhinopias. A lot of confusion is going on between these types and often divers are given the incorrect names by their guides as well. These Rhinopias can grow to a size of 20 to 25 cm.
What are the differences between these species?
Let’s quickly look at the main differences between the three species divers can encounter:
Paddleflap (Rhinopias eschmeyeri)
The paddleflap has few tentacles and a uniform colour. It’s first dorsal fin is sail-like with none or only small incisions between the dorsal spines. The most common colour is pale pink and darker pink, yellow, green, red and brown paddleflap are rarer.
This species is found on muck dive sites.
Weedy (Rhinopias frondosa)
This species has many tentacles, spots, round markings and deep incisions between the dorsal spines. The weedy Rhinopias come in all kinds of colours, including yellow, purple, red, brown and many more and they change their appearance to match their surroundings. Those living in an algae-rich environment grow more weed-like appendages than those living around coral or sponges.
This species is found on muck dive sites.
Lacy (Rhinopias aphanes)
This species has many tentacles, elongated markings and deep incisions between the dorsal spines. Unlike the other two species, it is found on reefs around Papua New Guinea including New Caledonia, Vanuatu and northeastern Australia.
How can divers identify different Rhinopias species?
The weedy Rhinopias is difficult to tell apart from the lacy Rhinopias but it can be done. The differences are to be found in the distribution, the habitat and the markings. Weedy Rhinopias live on mucky, sandy or gravel grounds and can be encountered all over the Indian and Eastern Pacific Ocean. Lacy Rhinopias are only found in the oceans around Papua New Guinea.
Any Rhinopias that is found in Indonesia or the Philippines is either a weedy or a paddleflap. If you find a Rhinopias in the region of Papua New Guinea on a muck dive site, it most probably is a weedy or paddleflap as well. Only a Rhinopias sitting on a coral reef in that region is likely to be a lacy scorpionfish.
Can divers see other types of Rhinopias?
The other three types of Rhinopias are rarely encountered by scuba divers and are all endemic to a small region. The R. argoliba has been found in a bay in Japan, the R. cea in Easter Island and the R. xenops (also called strange-eyed Rhinopias) in Hawaii and Japan.
What are the best destinations to dive with Rhinopias?
The best chances to see a Rhinopias are destinations in Indonesia (Ambon, Alor and Bali, sometimes Lembeh) or the Philippines (Anilao) in Indonesia. The best place to find a lacy scorpionfish is Milne Bay in Papua New Guinea.