Longfin batfish

What it is

This marine ray-finned fish belongs to the spadefish and batfish family. Adults display a roughly circular body profile with a low hump on the nape. Their colouration shifts between silvery white, grey, and brown, often featuring dark bands through the eye and near the pectoral fin. A distinctive dark blotch sits under the pectoral fin, with another mark above the anal fin base. Juveniles look vastly different, resembling floating leaves with highly elongated pelvic and dorsal fin rays. These young fish are brownish, helping them blend into debris. As they mature, the fins shorten, and the body becomes more robust and silver. The species can reach a total length of 70 cm.

Where it lives

Its distribution spans the Indo-West Pacific, extending from the Red Sea and East Africa to Papua New Guinea. The range reaches north to the Ryukyu Islands and south to Australia, including Western Australia, the tropical north, and New South Wales. Records exist for the Bay of Islands in New Zealand. Following the 2004 Indian Ocean tsunami, it was reported in the Gulf of Mannar, India. Recent sightings have occurred in the Mediterranean Sea off Turkey and Israel. They inhabit shallow coastal zones and deeper offshore areas, often associating with floating seaweed, debris, and artificial reefs.

How it lives

This omnivore consumes plankton, sessile and small invertebrates, and marine algae. Small juveniles aggregate among floating debris, finding safety in numbers as they locate one another. As they grow, they become more pelagic, forming sizeable schools. These groups often shelter beneath large rafts of Sargassum seaweed, which typically accumulate after the wet season. The fish are social and peaceful, preferring the company of their own kind. They can change colour rapidly, shifting from silver to brown with darker banding before fading back again, likely as a response to their environment or mood.

Fish and people

Fishers catch this species using hook-and-line gear, palisade traps, spears, trawls, and hand nets. The flesh is not highly valued commercially, with taste descriptions ranging from excellent to weedy. In the aquarium trade, they are popular for their peaceful nature and social behaviour. They form schools with conspecifics but should not be housed with aggressive tankmates that might harass them. Buyers often purchase them when small, but they grow rapidly and can outgrow small home tanks, reaching up to 24 inches in captivity.

Questions people ask about Longfin batfish

Good reading and sources

• Platax teira on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data