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37. The False Stonefish or Devil Scorpionfish (Scorpaenopsis diabolus)


The False Stonefish or Devil Scorpionfish (Scorpaenopsis diabolus) is not a Stonefish but a Scorpionfish. This may be confusing for most scuba divers because it has many characteristics in common with both stonefish and scorpionfish species.

Its skin is often covered in algae and other fouling organisms, and its upwards-oriented mouth are both characteristics of the Stonefish (genus Synanceia). Being often partially buried under the substrate is a behaviour that also resembles that of Stonefish species.

The bright flamboyant colours displayed on the inner surface of its pectoral fins is a characteristic defined as aposematism, which the False Stonefish shares with all members of the genus Inimicus, a Stonefish subfamily member (Synanceiinae). However, the shape of its body is more in line with members of the scorpionfish family (Scorpaenidae).

The False Stonefish or Devil Scorpionfish has venomous spines, a characteristic that all members in the order of Scorpaeniformes have in common. Both scorpionfish and stonefish belong to this order. Although the venom delivered through its dorsal spines can inflict a painful wound, it is much less potent than that of all stonefish species.

The False Stonefish or Devil Scorpionfish comes in a wide variety of colours and hues, from dark brown to the typical reddish colour of most scorpionfish and sometimes even completely white, resembling a broken-off piece of dead coral. Turquoise blue or greenish-blue coloration has been observed on different occasions. It is also not unusual to find a specimen that bears different colours, like for example, a dark brown head with reddish specks and spots in combination with a white body and tail.

There is also a very specific characteristic that the False Stonefish or Devil Scorpionfish shares with a few other members of the big Scorpaenidae family; biofluorescence. When illuminated with ultraviolet light, like, for example, an underwater UV video light or torch, this Scorpionfish will light up in an orange to red hue.

The False Stonefish or Devil Scorpionfish is a common fish of the shallow tropical and subtropical Indo-Pacific waters. Its distribution ranges from Africa's east coast and the Red Sea in the west to the Marquesas Islands in the east, to southern Japan in the north, and south to Australia. This benthic fish is most likely to be found alone or in pairs on rubble or weedy coralline-rock bottoms of reef flats and in lagoons and seaward reefs to a maximum depth of 70m/230ft or so.

It can reach a total maximum length of about 30cm/12 inches.

This bottom-dwelling ambush predator swallows its prey whole, using its extremely large mouth. To do so, it relies on its ability to stay unnoticed to gap and suck in passing prey, such as different species of invertebrates and small fish.


Because of its camouflage, a near-perfect match in colour with its surroundings, it was important to blur the background slightly to make this scorpionfish more visible for the spectators. A little saturation boost of the orange and yellow colours in the Scorpionfish's jaws and pectoral fins was necessary to create a wow factor in this short underwater videoclip.

Filming location:

This short underwater videoclip has been filmed in Mauritius 🇲🇺

More on this topic:

For a more in-depth description about aposematism please go to our vlog post 111 or click on this link: https://www.beyondscuba.com/post/inimicus-lll-aposematism

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