Thicklip Grey Mullet
Thicklip grey mullet turn up along the entire Dutch coast and push well into estuaries, harbours, and canals — places most anglers walk past without a second look.
They're a genuine challenge: small mouths, a diet built around algae and detritus, and a wariness that punishes sloppy presentation. For anglers who enjoy the puzzle, they're one of the most rewarding fish the Netherlands has to offer.
Scientific Name: Chelon labrosus
Also known as Diklipharder, Harder, Diklip
- Torpedo-shaped, silver-grey body with a darker back and faint horizontal dark stripes running along the flanks.
- The defining feature: a noticeably thick, fleshy upper lip covered in tiny papillae — unmistakable up close and what separates it from thinlip and golden grey mullet.
- Two dorsal fins set well apart; small, toothless mouth positioned low on a flat head.
- Most fish caught run 30–55 cm; anything over 60 cm and 2 kg is a serious specimen, with a maximum around 75 cm and 4.5 kg.
What to know
Habitat Distribution
- Native to the northeastern Atlantic; common along the full Dutch North Sea coastline, moving into estuaries and tidal inlets as water warms.
- Regularly found in the Oosterschelde and Westerschelde, where tidal flow, harbour walls, and jetties give them plenty of algae-covered structure to graze.
- Tolerates a wide salinity range — schools push from full saltwater into brackish and even fresh water, appearing in canals and tidal rivers well inland.
- Depth range is shallow: typically 2–15 m, and often right at the surface in marinas and harbour basins during summer.
Key Locations
- Oosterschelde — tidal estuary with extensive harbour walls and jetties; well-documented mullet presence year-round.
- Westerschelde — large tidal estuary in Zeeland; mullet follow tidal flows and congregate near structure.
- Dutch North Sea harbours and marinas — large summer schools are regularly visible, making this the most accessible shore fishery for the species.
- Ghent–Terneuzen Canal (Terneuzen side) — documented mullet alongside flounder and eel in this brackish, industrialised waterway near the Belgian border.
Specific Spots
- Harbour walls, jetties, and lock gates with algae-covered stone or concrete — mullet graze these surfaces methodically and hold close to the structure.
- Surface or just sub-surface in marina basins during summer; schools are often visible, which lets you sight-fish rather than guess.
- Tidal current edges in estuaries like the Oosterschelde, where food gets swept along and mullet intercept it near the bottom of the tidal cycle.
- Canal mouths and sluice outflows where fresh and salt water mix — the Ghent–Terneuzen Canal is a documented spot, with mullet mixing alongside bream, flounder, and eel.
Thicklip Grey Mullet FAQ
Answers from onWater's species guide.
What are the best lures and bait for Thicklip Grey Mullet?
Bread dough is the go-to: a small, soft ball pinched onto a fine hook and fished just sub-surface. Fresh white bread works; keep it soft so it compresses on the hook without masking the point.
When is the best time to fish for Thicklip Grey Mullet?
Summer (June–September): peak season as fish move north with warming water and concentrate in harbours and marinas; schools are visible and most accessible. Spring (April–May): fish begin appearing along the coast and in estuaries as temperatures climb; numbers build through the season.
How do you catch Thicklip Grey Mullet?
Shore fishing from harbour walls, jetties, and canal banks is the standard approach in the Netherlands. Anglers present bread dough or sea lettuce on a light float rig, often sight-fishing to visible schools in marinas during summer.
What do Thicklip Grey Mullet eat?
Primarily grazes algae, benthic diatoms, and biofilm scraped from hard surfaces using that thick lip, this is why standard predator lures draw blanks. Match the diet with bread dough or sea lettuce rather than anything that imitates a baitfish. Also picks up small invertebrates and detritus from the bottom.
Where do Thicklip Grey Mullet live?
Native to the northeastern Atlantic; common along the full Dutch North Sea coastline, moving into estuaries and tidal inlets as water warms. Regularly found in the Oosterschelde and Westerschelde, where tidal flow, harbour walls, and jetties give them plenty of algae-covered structure to graze.
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