Planehead filefish
Fish · Last reviewed 2026-08-25
A tough-skinned, tiny-mouthed amphi-Atlantic filefish with a locking spine on its head — caught on both sides of the ocean and famous for stealing baits.
Safety: injury while handling fish — minor injury.
Catching Planehead filefish
Everything here on fishing for it. Each entry opens the page behind it.
- Ground
- When
- May — months recorded at the places that document it, not a season for the whole range.
- Where
- 1 place FishingHQ documents — strongest claim anywhere: recorded here · From the shore
A filefish is what happens when a fish evolves to eat things that do not run away and to be too awkward to eat itself. *Stephanolepis hispidus* is a small, deep, laterally compressed fish covered in skin like fine sandpaper, with a tiny mouth carrying a few chisel teeth and a stout spine on top of the head that locks upright and cannot be pushed down while it is engaged.
The mouth is the thing an angler notices. It is far too small to take a normal bait and perfectly sized to remove one piece by piece, which is why filefish are a byword for bait theft across their range. Catching one deliberately means a hook small enough to fit that mouth, which is size 12 or below, and a bait to match.
It is genuinely amphi-Atlantic and genuinely wide-ranging: Nova Scotia south along the United States, Bermuda, the Bahamas, the whole Gulf of Mexico and Caribbean and down to Uruguay in the west; the Canaries and Morocco to Angola including Madeira in the east. FishBase records a maximum of 36.9 cm and 0.364 kg over a depth range of 0 to 293 m, and gives it high resilience.
It is worth knowing on both sides of the Atlantic under the same English name, which is unusual: an angler on a Carolina pier and one on a Canarian breakwater are losing bait to the same fish and calling it the same thing.
Where Planehead filefish is documented
Places where public sources describe this species as fished, with how it is fished and how strongly the evidence supports it. This is not a range map and it is not a recommendation — it is what has been written down about a fishery rather than a record of any individual catch, and being listed is never permission to fish.
Lanzarote
1 documented place
Puerto del Carmen harbour, Lanzarote
Harbour wall
Recorded here
From the shore
Reported May
What these strengths mean
- Recorded here
- At least one credible public account of this species being caught here. That is all it means.
Identification
No photograph of Planehead filefish has passed identity review yet, so none is shown. FishingHQ publishes a species photograph only once somebody has confirmed the animal in it against the species record’s own diagnostic features.
- Scientific name
- Stephanolepis hispidus
- Family
- Monacanthidae
- Water
- Saltwater
- Conservation status
- Least Concern
- Regions
- North America, Caribbean, Central & South America, Western Europe, West Africa, North Africa
- Deep, strongly compressed, almost diamond-shaped body covered in rough sandpaper-like skin rather than obvious scales.
- A stout spine on top of the head, above or just behind the eye, which locks upright and cannot be folded while engaged.
- A very small mouth at the end of a slightly protruding snout, carrying a few chisel-shaped teeth.
- Mottled brown, olive and cream, often with darker blotches, and able to change shade against the background.
- Slow, fluttering swimming driven by the soft dorsal and anal fins rather than the tail.
Size
- Typical
- 12–20 cm
- Large
- 25–30 cm
Exceptional: FishBase records a maximum of 36.9 cm and 0.364 kg
Lifecycle and reproduction
Reef-associated over a depth range of 0 to 293 m, and frequently associated with floating weed and structure as a juvenile. High resilience.
Not detailed on the FishBase record for this species. Monacanthids generally deposit demersal eggs in a prepared nest with parental guarding, and that is not asserted here as established for this fish.
Feeding and senses
Picks small invertebrates, weed and encrusting growth from structure with a tiny, precise mouth. That precision is the whole of its reputation: it removes a bait in fragments without ever taking the hook, and an angler who does not scale down will feel bites all afternoon and land nothing.
Close-range sight, working over structure slowly rather than hunting. It is not driven off by movement above and can often be watched taking a bait, which is a useful thing when working out what size of hook it will actually fit.
Through the year
Resident year-round over structure through the warm parts of its range, and a summer visitor at the cold ends of it — the Nova Scotian records are not a year-round population. Juveniles associate with drifting weed, so a stretch of coast can produce small filefish when a weed line comes in and none at all when it does not.
Distribution
Western Atlantic: Nova Scotia, Canada south along the U.S., Bermuda, the Bahamas, throughout the Gulf of Mexico and Caribbean Sea, and along South America to Uruguay . Eastern Atlantic: Canary Islands, Morocco to Angola including Madeira
This is a biological range — where the species occurs, not a prediction that you will catch one. To browse the fishing geography FishingHQ holds, start at fishing places.
Why anglers care
Known to anglers on both sides of the Atlantic principally as a bait thief, and a legitimate light-tackle target for anybody prepared to fish a hook small enough — size 12 and below — to fit the mouth. Taken from breakwaters, piers and structure on the smallest scraps of prawn, worm and shellfish. It is eaten in some parts of its range and is difficult to prepare because of the skin.
Handling and returning
The locking head spine is the thing to know about. It engages upright and will not fold while locked, so a fish gripped carelessly drives it into a palm; it releases when the small second spine behind it is depressed. Hold the fish across the body clear of the spine, unhook with pliers, and do not try to force the spine down.
Safety
Injury while handling fish — Minor injury
The dorsal head spine locks in the upright position and cannot be pushed flat while it is engaged, so a hand closed over the back of the fish is punctured by a spine that will not give.
What reduces it: Grip the fish across the flanks below the spine rather than over the back, unhook with pliers, and release the spine by depressing the small trigger spine behind it rather than by forcing it.
Where to go next
Where it lives
More fish
Not related to this page — just the rest of the section. There is little else joined to this subject yet, and a short page should still lead somewhere.
Sources and evidence
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Family, maximum size, depth range, environment, distribution and the IUCN assessment for Stephanolepis hispidus.States this directlyPassage read and verified
- The IUCN Red List of Threatened Species — International Union for Conservation of Nature (Conservation authority)Relied on for: The Least Concern assessment for Stephanolepis hispidus, assessed 27 February 2014.States this directlyCitation checked — the work exists and is described correctly
- Species hunting adventures on Lanzarote — a four-part shore diary with a full tally — Something Fishy Going On (angling blog), parts also posted to World Sea Fishing, 2014 (Practitioner report)Relied on for: That this species is taken from named public shore marks on Lanzarote, how many were caught across one week in May, and the light-tackle methods and baits that took them.States this directlyPassage read and verified
Why the 2 connections on this page are here, and the sources
How it is caught
Reported, not established — 1 connection
Reported, but without independent support. Recorded because it is in circulation, not because it has been shown to hold.
Light rock fishing
Recorded once from the outer breakwater on light tackle. The mouth is too small for an ordinary bait, so a hook of size 12 or below is not finesse but a requirement, and that is what puts it in this method rather than any other.
- Species hunting adventures on Lanzarote — a four-part shore diary with a full tally — Something Fishy Going On (angling blog), parts also posted to World Sea Fishing, 2014 (Practitioner report)Relied on for: The light-tackle methods, rigs, lures, baits and hook sizes a species-hunting angler used on Lanzarote, and the species each took.States this directlyPassage read and verified
Where it lives
Backed by research — 1 connection
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
Rocky shores and reefs
Recorded as reef-associated over a depth range of 0 to 293 m on both sides of the Atlantic. Its tiny mouth is an apparatus for picking growth off hard surfaces, so the structure is the food rather than the shelter.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Environment, depth range, habitat association and distribution for Stephanolepis hispidus.States this directlyPassage read and verified
How FishingHQ labels evidence is explained in the evidence policy.