Rare and deadly Scorpionfish that changes colour found in Indian waters

A scorpionfish that changes colour in four seconds and carries a neurotoxin in its spine to hunt its prey has been found in Indian waters for the first time, providing yet another proof of the diversity of Indian marine resources.

Scientists at the Kochi-based Central Marine Fisheries Research Institute have found the rare scorpionfish from Sethukarai coast in the Gulf of Mannar -popular as the site for the mythological bridge built by Lord Rama to reach Lanka (Sri Lanka).

Camouflaged within the seagrass meadows, the band-tail scorpionfish (Scorpaenospsis neglecta) is known for its stinging venomous spines and its ability to change colour.

"During the underwater survey, the species was first sighted as a coral skeleton. On first look, its appearance was totally confusing as to whether it was a fish at all or fossilised coral skeleton covered with bivalve shells. It started changing its colour the moment we disturbed it by touching a dead coral fragment. Within four seconds, the skin of the fish changed from white to mottled black colour”, said R Jeyabaskaran, senior scientist at CMFRI who led the team of researchers in finding the fish.

This is the first reporting of the species in Indian waters. Its ability to change colour helps the fish blend with its surrounding to escape from predators while hunting its prey.

The fish gets its unique name because like a scorpion, it too stings its prey with a deadly venom. “When the spines pierce an individual, the venom gets injected immediately and it can be extremely painful. Eating this fish would lead to fatal death," Jeyabaskaran said.

A nocturnal feeder, the band-tail scorpionfish lays motionless in the sea bottom and waits for the prey to come close to it. Most of them feed during the night with an ability to attack and suck its prey at lightning speed.

Having a highly powerful sensory system, it could even detect respiratory ventilation flows produced by crabs at a distance of 10 cm in a dark environment.

Unlike other fishes, band-tail scorpionfish uses its lateral sensory system instead of eyes to hunt its prey. It mainly feeds on small benthic fishes like gobies and blennies, crustaceans and other benthic macro invertebrates found in coral reefs, rocks and algal beds.

The specimen has been deposited in the National Marine Biodiversity Museum of the CMFRI. A research paper describing the discovery has been published in the latest issue of the journal Current Science.