This article will teach you how to differentiate the three most common species of scorpionfish we encounter in the Andaman Sea: the Bearded Scorpionfish, Devil Scorpionfish and Stonefish.

These three species are often mistaken for one another because they are quite similar and belong to the same family. However, once you know what to look for, there are some simple ways to tell them apart during your next dive in Thailand or Myanmar.

Let’s start with their similarities:

• These members of the Scorpaenidae family live on the ocean floor, often hiding among coral reefs, and swim about as well as a chicken can fly!
• They have large heads with strong bony cheeks and surprisingly wide mouths capable of swallowing relatively large prey.
• They are not aggressive, but their dorsal spines are highly venomous. If threatened, they can raise their spines as a defence before quickly escaping to a nearby hiding place.
• They are all sedentary ambush predators, using the same passive hunting strategy as a gecko. You will rarely see them move anything other than their eyes, except when they suddenly swallow prey that has ventured a little too close.

Stonefish belong to the Synanceia group and are usually quite large, measuring around 30 to 40 cm. Their rounded bodies can look exactly like a stone covered in sand, while their leathery skin may be brown, grey, yellow, white, pink or even purple.

Their skin is often covered with sponge, algae or other growth that matches the surrounding reef, making them extraordinarily difficult to see. This is one reason why Stonefish deserve particular respect from divers.

There are also several useful details to look for. Scorpionfish generally have eyes that protrude slightly from the head, whereas a Stonefish’s eyes are much more difficult to distinguish, being recessed into the head above its characteristic down-turned, grumpy-looking mouth.

Stonefish also have thicker spines and larger dorsal fins, although these are usually well hidden along the body. Their tail tends to curl more noticeably at the end, whereas the tail of a typical scorpionfish is comparatively straight.

Stonefish are among the most venomous fish in the world, which is another very good reason to be careful where you put your hands while diving. In fact, the safest rule is simple: never touch anything underwater.