Everything you should know about scorpionfish

Scorpionfish are the lesser-known cousins of the infamous stonefish, the most venomous fish in the world. They are just as venomous but slightly prettier, as far as fish that look like stones go…

We house several false stonefish (Scorpaenopsis diabolus) at the Two Oceans Aquarium. They are members of the family Scorpaenidae, which comprises scorpionfish and relatives.

As you may guess from its name, false stonefish are not “true” stonefish but scorpionfish! They are also known as devil scorpionfish.

False stonefish can be differentiated from their cousins, the “true” stonefish, by a bump on the back of the head, slightly wider mouths, and body shape. Stonefish are lumpier in appearance, while false stonefish have a distinctly humped back, a large head, an upturned jaw, and a characteristically fish-like body shape.

False stonefish have numerous defence mechanisms as ambush predators. Their dorsal fins have 12 short, thick venomous spines. These spines are flared up when stonefish are disturbed by potential predators – this is a natural defence mechanism and not a method of predation.

Scorpionfish, as masters of camouflage, blend seamlessly into the surrounding substrate of coral, rock, and seafloor. These fish lie on the seafloor waiting for prey to swim past before lunging forward and gulping the prey into their large mouths. Often, scorpionfish lie so still on the seafloor that algae start to grow on them!

The inner part of their pectoral fins is yellow with a large black spot. When threatened, false stonefish flare these fins to expose the bright colours and startle potential predators.

While not the most beautiful marine animal, scorpionfish are much more interesting than their drab appearance suggests… On your next visit to the Aquarium, see how many scorpionfish you can spot in the Poisonous or Venomous Exhibit.