Greenback Flounder
Greenback flounder are a South Island species, concentrated along the Canterbury Bight and Southland coasts.
They're a bottom-dwelling flatfish taken by shore and estuary anglers using light bait rigs, and occasionally picked up by trout fishers working South Island rivers. The eating quality is excellent, which keeps a loyal local following targeting them.
Scientific Name: Rhombosolea tapirina
Also known as Pātiki, greenback
- Oval-shaped body with a dark green back and white belly — the green back is the key ID feature separating it from the yellow-belly flounder.
- Both eyes sit on the right side of the body; the lower eye sits noticeably forward of the upper.
- Grows to around 50 cm, making it one of the larger flounder species in New Zealand waters.
What to know
Habitat Distribution
- Native to New Zealand; the local population is genetically distinct from Australian populations.
- Found almost exclusively along the east and south coasts of the South Island, from Otago south through Southland, down to depths of around 460 metres.
- Key fishing areas are the Canterbury Bight and Southland — these are the concentrations that matter to anglers.
- Also moves into estuaries and river mouths, and has been encountered well upstream in South Island rivers such as the Temuka.
Key Locations
- Canterbury Bight — one of the two main commercial and recreational fishing areas for this species on the South Island east coast.
- Southland coast — the other primary concentration, fished from shore and by small boats.
- Waitaki River mouth (Otago/Canterbury border) — a known spot where anglers intercept fish moving between estuary and river.
- Temuka River (Canterbury) — greenbacks have been caught well upstream of the estuary, encountered by trout anglers working the lower reaches.
Specific Spots
- Estuary channels and river mouths are productive — greenbacks follow tidal movement into these areas to feed over sandy and muddy bottom.
- River mouths like the Waitaki attract fish; rolling a light weight down moving current through the channel can find them beyond the estuary proper.
- Flat sandy bottom in the Canterbury Bight is core habitat — fish work these areas close to the seafloor where they can ambush bottom-dwelling prey.
- In rivers, look for fish moving slowly upstream in clear water — they're visible and approachable, unlike trout.
Greenback Flounder FAQ
Answers from onWater's species guide.
What are the best lures and bait for Greenback Flounder?
Worm on a small single hook under a running sinker rig is the go-to natural bait, simple and effective in estuaries and river mouths. Small soft-bait lures (paddle tails or grubs) on a 1/16–1/8 oz jig head, worked slowly along the bottom, will take fish at river mouths and in tidal channels.
What flies work for Greenback Flounder?
Tiny nymphs, Pheasant Tail or Hare's Ear patterns (both imitate aquatic insect larvae) in sizes 14–16, cast ahead of fish spotted moving upstream in clear South Island rivers.
When is the best time to fish for Greenback Flounder?
Summer and autumn (December–April), fish are inshore and in estuaries after the winter spawning migration, making them most accessible to shore-based anglers. Winter (June–August), adults move offshore into deeper water to spawn and are largely out of reach of recreational gear.
How do you catch Greenback Flounder?
Most anglers target greenbacks from shore or by wading estuary channels and river mouths along the South Island east coast, using light bait rigs fished on the bottom. A smaller number pick them up incidentally while nymphing for trout in South Island rivers, where the fish are visible and can be cast to directly.
What do Greenback Flounder eat?
Feeds on small invertebrates and bottom-dwelling organisms, worms are a proven natural bait, fished on a light running rig with a small single hook close to the bottom.
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