Stephanolepis hispidus
Spot planehead filefish across Florida, Brazil and the Caribbean. Know what to look for and when, sightings peak in September in the Northern Hemisphere.
Roughly hand-sized at around 25 cm, this fish has a deep, laterally flattened body, like a dinner plate with a tail, covered in sandpaper-rough skin that ranges from pale grey to olive-brown with irregular darker mottling. The giveaway feature is the single stout spine on top of the head, which can be raised or folded flat. Colour and pattern shift constantly to match surroundings, so focus on body shape and that telltale spine rather than markings. The small, pursed mouth sits at the tip of a slightly concave face profile.
Planehead filefish tend to hover close to structure, seagrass beds, rocky reefs, and floating sargassum mats are all favoured haunts, often orienting head-down or at an angle to blend into the background. They are not fast movers and will usually hold position or drift slowly away if approached, making them possible to observe at close range with a calm, unhurried approach. As omnivores, they graze methodically, picking at algae, small invertebrates, and detritus with those characteristic nibbling bites from a tiny, precise mouth.
Planehead filefish are one of the species commonly associated with floating sargassum, the free-drifting seaweed that acts as open-ocean nursery habitat, juveniles in particular use it for shelter and food during their early pelagic (open-water) phase before settling to the reef.
Northern Hemisphere data point to September as the peak month for sightings. The species tolerates water temperatures from about 16 to 28 °C, so it is not strictly a warm-season specialist, but late summer appears to be when divers encounter it most reliably.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most commonly logged across Florida and the broader US Southeast coast, which accounts for the largest share of sightings by a clear margin. Brazil, particularly the Rio de Janeiro and São Paulo coastline and the Northeast Coast, is the next strongest region, followed by Cuba's Jardines del Rey, Venezuela's Central Coast, and the waters around Colombia's Caribbean Coast. The Bahamas and Gozo in Malta also appear in the records, reflecting this species' surprisingly broad Atlantic range.
Mapping where Planehead Filefish is logged…
Florida and the US Southeast coast are the strongest areas for sightings by a wide margin. Brazil, especially the Rio de Janeiro region and the Northeast Coast, is also well represented, along with Cuba's Jardines del Rey, Venezuela's Central Coast, the Colombian Caribbean, and the Bahamas. The species has even been recorded in European waters around Gozo, Malta.
In the Northern Hemisphere, sightings cluster in September based on recorded dive data. The species tolerates a wide temperature range, roughly 16 to 28 °C, so it can be present outside peak season, but late summer is the most reliable window.
Look for a deep, plate-shaped body about 25 cm long with rough, sandpaper-like skin in mottled grey or olive-brown tones. The raised spine on top of the head is the clearest field mark. The small pursed mouth and slightly concave face profile also help separate it from other reef fish of similar size.
Typical adults reach around 25 cm, roughly the length of a hand and forearm. They are not large fish, and their flattened shape can make them look even smaller when viewed head-on, which is part of why they are easy to overlook against a reef or seagrass bed.
At most sites where they are recorded, planehead filefish are logged as uncommon, and at a good number of sites as rare. Common sightings do occur but are the exception. A slow, attentive dive along seagrass or rubble habitat gives the best chance, they blend in well and do not advertise themselves.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Planehead Filefish
435 sites
