Region: Philippines

Appearance
Scrawled filefish blend in for safety. Covered by numerous blue, broken stripes formed of dashes and dots, black spots and sporting a variety of shades of gray, tan, brown and olive, the scrawled filefish pales or darkens its skin to blend with its background. Many times, predators swim right on by not even noticing the scrawled filefish.

Sharing this feature with their close relatives the triggerfish, filefish use spines for safety. When threatened, a filefish dives into a hole or crevice in the reef, then wedges itself into the shelter by erecting the large dorsal spine on its head. The spine is locked into place by a second, smaller spine behind it. Another spine on the fish's belly extends to help wedge the fish securely into its shelter. In case of an emergency, the powerful jaws grasp the wall of the hole providing additional security. Filefish also use this wedging behavior at night when they rest within the reef.

While the scrawled filefish is a slow swimmer, the broom-like tail provides thrust for short burst of speed to make a quick dash for safety inside the reef. When pursued, filefish sometimes make grunting sounds. The eyes of this wary fish are set high on its head and can move independently so that it can scan the reef for food and predators.

With tiny spines on the scales, filefish have rough skin like that of sharks. Years ago, fishers used to use the skin of filefish to light matches because it is so coarse.

This is the longest species of filefish, which can be up to 3.5 feet (110 cm) long and weigh 5.5 pounds (2.5 kg).

Habitat
Scrawled filefish live alone on lagoon and seaward reefs at depths of 3 to 400 feet (1 to 120 m). Juveniles and occasionally adults may live in the open ocean floating around within the safety of Sargassum weeds, which is a leafy golden brown algae that floats freely throughout the ocean with small air bubbles or bladders. Catching a free ride inside these weeds allows the scrawled filefish to inhabit many oceans.

This filefish will orient itself vertically to blend in with blades of seagrass and coral whips. It will also float completely still in a vertical position next to the dark opening of a coral cave or hole, to hide from predators.

Range
Scrawled filefish live in the warm parts of all the Oceans.

Diet
The scrawled filefish can be poisonous because of what it eats. This fish eats the poisonous blue-green algae that grows on dead coral. They will also eat other kinds of algae, seagrass, sea squirts, soft corals and sea anemones.

Reproduction
Filefish breed in harems, which means there is one male for a group of two to five females. The males are territorial, which means they ferociously guard the territory where the eggs are laid.

The females will lay demersal eggs, or eggs on the ocean floor. She puts them in a safe place, like a hole in the sand, and then the male fertilizes them. Either the female or the male guards them from predators. When guarding the nest the filefish will attack any creatures, even unknowing divers, who wander too close. The female looks after the fry or baby fish.

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Threats and Management
Scrawled filefish used to be caught and sold at markets as food, but fishers are targeting these animals less and less. They have high amounts of ciguatera fish poisoning, a type of toxin commonly found in fish. Eating fish with ciguatera causes an illness that can result in stomach and digestive related problems, some severe phsiological problems including severe headaches, soreness of the muscles, changes in blood pressure and heart problems, and sometimes even death. Although the scrawled filefish is said to be tasty, it is highly recommended that you don’t eat it. This may be the reason the population of scrawled filefish has remained stable.

References
Web Sites:
NOTE: The following Web sites are not maintained by the John G. Shedd Aquarium and will open in a new browser window.

Fishbase:
http://filaman.uni-kiel.de/Summary/SpeciesSummary.cfm?
ID=4275&genusname=Aluterus&speciesname=scriptus

Print Publications:
Coleman, N. 1999. Dangerous Sea Creatures Aquatic Survival Guide. Australia: Neville Coleman’s Underwater Geographic Pty Ltd. 95p. ISBN# 0-947325-24-7.

Debelius, H. 1999. Indian Ocean Reef Guide. Frankfurt, Germany: IKAN. 321p.
ISBN# 3-9317-0267-7.

Hauser, H. 1984. Book of Marine Fishes. Houston, Texas: Gulf Publishing Company. 192p. ISBN# 1-55992-025-4.

Hoover, J.P. 1993. Hawaii’s Fishes. A Guide for Snorkelers, Divers and Aquarists. Honolulu, Hawaii: Mutual Publishing. 183p. ISBN# 1-56647-001-3.

Myers, R.F. 1999. Micronesian Reef Fishes. Barrigada, Guam: Coral Graphics. 216p.
ISBN# 0-9621564-4-2.

Perrine, D. 1997. Mysteries of the Sea. Lincolnwood, Illinois: Publications International, Ltd. 312p. ISBN# 0-7853-2430-5.

Reader’s Digest. 1984. Reader’s Digest Book of the Great Barrier Reef. Sydney, Australia: Reader’s Digest Services Pty Limited. 384p. ISBN# 0-949819-41-7.

Vocabulary Words

Ciguatera fish poisoning – A form of human poisoning caused by the consumption of subtropical and tropical marine fish which have accumulated naturally occurring toxins through their diet. The toxins are known to originate from several dinoflagellate (algae) species.


Demersal eggs – Eggs that are laid on the ocean floor.


Extinction – An organism that has not been present on the face of the earth for over 50 years.


Fry – Baby fish.


Harem – A group of females that mate with one male.


Organism – A living thing.


Sargassum weed – A leafy golden brown algae that floats freely throughout the ocean with small air bubbles or bladders. This algae can house many small animals like small fish, worms, shrimp, crabs and jellies. Some of these animals only live within the safe confines of the Sargassum weed.


Species – A group of organisms capable of breeding and producing fertile offspring; organisms that share the same gene pool.


Territorial – An animal that lives in the same area all the time. This animal reproduces in this area and fiercely defends it.

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