SCUBA News 255
(ISSN 1476-8011)

SCUBA News (ISSN 1476-8011)
Issue 255 - September 2021

Welcome to SCUBA News - thank you very much for subscribing. For readers in the UK some good news this week: previously out-of-bound diving destinations, such as Egypt, Oman, the Maldives and Turkey, have been removed from the UK's Red List. When you return from these countries you will no longer have to quarantine in a hotel for 11 nights.

What's New at SCUBA Travel?

Caribbean Reef Shark

Splendid Saba

A marine park entirely encircles Saba's rocky coast in the northern Caribbean, and there is some outstanding diving there.

Pink soft coral and fish

Diving in Jordan

The best time to dive Jordan's Red Sea is in October and November for healthy corals, fish & turtles.

Save up to 16% on Egypt liveaboard

Egypt liveaboard

Blue Force 2 visits some of the best reefs and wrecks of the northern Red Sea.

Get Deal…

Creature of the Month: Picasso Triggerfish, Rhinecanthus sp

Trigger fish have deep bodies, high eyes, small mounths and colourful patterns - no more so than the Picasso Trigger Fish.

Five of the six species of the Rhinecanthus genus are known as Picasso Triggerfish (or just Picasso Fish). They are all between 23 and 30 cm long and mostly live in shallow water, less than 20 m deep. You will find them on the reefs of the Red Sea, Arabian Gulf, Great Barrier Reef, Pacific and Indian Oceans. As adults they are mainly solitary, but the young fish may live in schools.

Picasso triggerfish
Arabian Picasso Trigger Fish, Rhinecanthus assasi, taken in Soma Bay, Egypt. Photo credit: Amada44, (CC BY-SA 4.0)

Picasso triggerfish feed on a wide variety of animals living on the bottom: fish, invertebrates and algae. To find worms to eat they will blow a jet of water to move the sand. They like sea urchins and will upturn them to avoid the spines before eating. The triggerfish's eyes are very high up, which may be to prevent them getting spiked the tasty urchins. Rhinecanthus sees in colour and studies show it prefers red food, followed by green.

Picasso triggerfish blackbelly
Blackbelly Picasso Trigger Fish, Rhinecanthus verrucosus, Indo-West Pacific. Photo credit: Bedo, (CC BY-SA 4.0)

An attractive fish with blocks of colour on a white and beige background. Unlike some trigger fish, these aren't commonly aggressive towards divers.

Reef Picasso triggerfish
Reef Picasso Trigger Fish, Rhinecanthus rectangulus, taken in Hanauma Bay, Hawaii. Photo credit: Qyd

Trigger fishes are so called because of the shark-fin shaped trigger they are able to raise in defense. They use this to jam themselves into a crevice in the coral. The trigger is actually the first spine of its dorsal (top) fin. They bend the second spine forward to fix the first firmly in position. When the fish is swimming the fin is flattened into a groove.

Triggerfish are territorial. Some picasso triggerfish maintain their territories for more than 8 years. For R. aculeatus, each male territory overlaps 2 or 3 female territories. The females lay their eggs in nests on the sea bed and guard them well. It is more usual for male fish to protect eggs, but as one male mates with each of the females on overlapping territories, less eggs would be fertilised if the male spent his time "standing" guard.

Lagoon Picasso triggerfish
Lagoon Picasso Trigger Fish, Rhinecanthus aculeatus, Indo-Pacific. Photo credit: Arpingstone

Class: Actinopterygii > Order: Tetraodontiformes > Family: Balistidae > Genus: Rhinecanthus

For more featured creatures see the marine life highlights.

References and Further Reading

Coral Reef Fishes, Indo-Pacific and Caribbean, by Ewald Lieske and Robert Myers, Harper Collins
Part I, Fishes, by Farid S Atiya, Elias Modern Printing House, 1994
Cheyney et al. (2013). Colour vision and response bias in a coral reef fish. J Exp Biol. 216 (15): 2967-2973.
Tetsuo Kuwamura. (2010). Evolution of Female Egg Care in Haremic Triggerfish, Rhinecanthus aculeatus. J. Ethology.

Diving News From Around the World

Our round up of the best underwater news stories of the past month. For breaking news see our Twitter page or RSS feed


Enter Now: Ocean Art 2021 Underwater Photo Competition
The 10th annual Ocean Art contest is now accepting entries. A long list of prizes valued at over $30000 are up for grabs for both amateur and professional photographers.

Coral reef

Travel opens up from UK to top diving areas like Egypt and the Maldives
Previously out-of-bound diving destinations, such as Egypt, Oman, the Maldives and Turkey, have been removed from the UK's Red List. People arriving from these countries will no longer have to quarantine in a hotel for 11 nights


Coral reefs are 50% less able to provide food, jobs, and climate protection than in 1950s, putting millions at risk
Global coverage of living corals had declined by about half since the 1950s and consequently, the diversity of species had also declined, by more than 60 per cent.

Loggerhead turtle

Loggerhead turtles born as far north as Venice
This is the first time that the hatching of Caretta Caretta turtle eggs had been recorded along the northern Adriatic coast.

Sealion in the Galapagos

Ecuador eyes new Galapagos marine reserve to limit commercial fishing
Ecuador's government is considering creating a new marine reserve near the Galapagos Islands to protect migratory species of turtles, whales and sharks threatened by industrial fishing and climate change.

coast of Dunbar

Instructor fined after pupil dies in deep water dive to find German submarine
A diving instructor has been fined after one of his pupils died in a "highly traumatic incident" during a deep dive in Scotland.

Investigating illegal fishing

Indonesia's newly minted investigators to go after illegal fishing kingpins
Indonesia's fisheries ministry has pledged to target the ultimate beneficiaries of fisheries-related crimes in the country.

basking shark courtship

Basking sharks disappearing from Isle of Man but congregating off Ireland
SEvery summer hundreds of basking sharks used to visit the Isle of Man, but recently there have been fewer and fewer.

Coral closeup

Some coral reefs can keep up with ocean warming
Some coral communities are becoming more heat tolerant as ocean temperatures rise, offering hope for corals in a changing climate<

SCUBA News is licensed under a Creative Commons Attribution 4.0 Unported License. This means we are happy for you to reuse our material for both commercial and non-commercial use as long as you: credit the name of the author, link back to the SCUBA Travel website and say if you have made any changes. Some of the photos though, might be copyright the photographer. If in doubt please get in touch.

Photo credits: Tim Nicholson, Jill Studholme, Kristin Riser, Jianye Sui

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