Similan Islands scorpionfish



As the name suggests, scorpionfish (Scorpaenidae) are venomous. They have a ‘sting’ similar to scorpions found on land. With sharp spines covering their body, which are coated with venomous mucus, divers should be wary around these fish. They are widespread in tropical and warm oceans, but mostly found in the Indo-Pacific.

It is a source of debate about the number of species of scorpionfish. There are approximately 10 subfamilies and a total of 388 different species of scorpionfish, all with varying levels of venom. Some of the most well-known include the stonefish, lionfish and devilfish.

Similan Islands scorpionfish

Distinguishing features

Scorpionfish all tend to look fairly similar. The have compressed bodies and crusty looking ridges all over their body. There are anywhere between one and seventeen venomous spines on their head and back. The spines within the dorsal, anal and pelvic fins all have venom glands at their bases.

It may be extremely hard to spot or identify scorpionfish whilst diving as these marine creatures rely heavily on camouflage. Their natural colouring and markings help them to blend in with their surroundings. Scorpionfish are usually brown, black, yellow, white, red or orange. Some species can change colour to disguise themselves better.

The sizes between species vary widely; a scorpionfish can grow between 14cm and 45cm.


Usually, scorpion fish live in shallow waters, which can pose a hazard for beach goers. The reefs and sand help to disguise them, and they also can be found around rocky crevices or hiding under overhangs.

Feeding habits

As bottom-dwellers, scorpionfish are omnivores and feed mainly on crustaceans and smaller fish. They wait for their prey by disguising themselves amongst the coral or lying on the sand. When their prey passes, they quickly attack before it can get away. Scorpionfish are suction feeders and capture their prey by rapidly projecting a suction field, generated by the fish’s buccal cavity.


Before mating, scorpionfish release a floating mass of gelatine type material in which to embed their eggs. Then, the female scorpionfish releases between 2,000 and 15,000 eggs, so they can be fertilized by the male scorpion fish. As the eggs float away, the mating pair quickly hide to avoid attracting the attention of predators to their eggs.

Life cycle

Scorpionfish eggs hatch extremely quickly, after only two days. The young fish stay need the surface of the ocean until they grow into juveniles. They then swim down to the ocean floor and make their home amongst the reefs. Very little has been recorded about the life span of scorpionfish in the wild, possibly due to their superb camouflage making them difficult to study.

Scorpionfish factoids

  • A popular choice for saltwater aquariums due to their interesting appearance and unusual behavior.
  • A dominant predator in its environment, but also hunted by larger fish and sea lions.
  • Their spines can cause painful, deep wounds if a human steps on one of these fish.

This post is also available in: Thai

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.