The Scribbled Filefish (Aluterus scriptus), also known as the Scrawled Filefish or Scribbled Leatherjacket, belongs to the Monacanthidae family. It’s often mistaken for a triggerfish, but here’s the lowdown: triggerfish are actually from the Balistidae family. Even though they look alike, triggerfish and filefish are from different families. However, both belong to the same order of highly derived ray-finned fish, Tetraodontiformes.
This order includes ten marine fish families:
- Triggerfishes (Balistidae)
- Filefishes (Monacanthidae)
- Boxfishes (Ostraciidae)
- Pufferfishes (Tetraodontidae)
- Spiny Pufferfishes (Diodontidae)
- Ocean Sunfishes (Molidae)
- Moorish Idols (Zanclidae)
- Cowfishes (Lactariidae)
- Longhorn Cowfishes (Lactariidae)
Each family has its own unique features and behaviors!
Distinguishing Features
Scribbled Filefish get their name from the vibrant, bright patterns on their bodies that look like they've been doodled with a colorful pen. Their scientific name, scriptus, even means "written"!
These fish have diamond-shaped, flattened bodies and broom-like tails with a distinctive, upturned mouth at the front. Their teeth are moderately strong, with six or fewer in the outer row on both the top and bottom jaws. They have oblique gill openings and no pelvic fins. The long, rounded tailfin often has a ragged edge.
Their color ranges from pale gray to olive-brown and can shift to blend in with their surroundings. They’re decked out with bright blue lines and black dots. If you spot a Scribbled Filefish at a cleaning station or on the hunt, watch closely - their colors can flash electric blue!
Fully grown, these fish typically measure 56 to 80 cm long, but some can reach up to 109 cm. They usually weigh a few kilograms, though the heaviest recorded was over 2.5 kg!
Defensive Behavior
Scribbled Filefish use both camouflage and spines for protection. When threatened, they quickly dive into a reef crevice, wedging themselves in by raising the dorsal spine on their head. This large spine locks into place with a smaller spine behind it, while another spine on the belly helps secure the fish in the crevice. They use this same method for protection while resting on the reef at night.
Feeding and diet
Scribbled Filefish are omnivores with a taste for variety. They snack on algae, small invertebrates like hydrozoans and gorgonian corals, and small crustaceans and worms. They're even skilled at munching on the gelatinous jellyfish. Unlike some marine animals that hunt at specific times, Scribbled Filefish feed when food is abundant, without a set day or night schedule. Juvenile Scribbled Filefish often swim in a vertical, head-down position when associated with drifting vegetation to avoid detection by potential predators.
Reproduction
Scribbled Filefish are usually solitary except during breeding seasons, when they form small groups of one or two males and two to five females. Females lay eggs in shallow hollows on the ocean floor, and males fertilize them. Both males and females guard the nest from predators during incubation, but females take care of the hatched fish. Reproduction can occur multiple times a year, often when food is plentiful, because of the warm waters they inhabit.
Predators
- Scribbled Filefish are preyed upon by larger fish like Mahi Mahi and bluefin tuna.
- Scribbled Filefish can get parasites such as the copepods Caligus haemulonis and C. ballistae, and the monogenean Neobenedia melleni. These parasites live on or inside the fish and can affect its health.
- Humans also prey on Scribbled Filefish . They’re considered gamefish in some areas and are frequently collected for the aquarium trade, but they don’t do well in captivity.
Where to Find Scribbled Filefish on Koh Tao
You can spot Scribbled Filefish at several dive sites around Koh Tao. They can be a bit shy, but you’re likely to find them hanging out at various shallow dive spots across the island:
