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Common Smelt

Common Smelt

Common smelt are small, native, schooling fish found in rivers, estuaries, and lakes across New Zealand. Most anglers encounter them as baitfish — they're a primary food source for brown trout and are used by whitebaiters and trout anglers alike.

Their cucumber-like scent makes them instantly recognisable in the hand.

Scientific Name: Retropinna retropinna

Also known as Silveries, cucumber fish

Physical Characteristics:
  • Slender, elongated silver-green body with clear fins; adults typically 90–100 mm, with the largest on record reaching 165 mm.
  • Distinctive adipose fin — a small fleshy nub on the back between the dorsal fin and the tail — separates smelt from most other small NZ fish.
  • Forked tail and fine scales; the whole fish has a noticeable fresh-cucumber smell, which is the easiest field ID.
  • Nearly identical to Stokell's smelt; the two are reliably told apart only by scale size and count — common smelt have larger, coarser scales.

What to know

Habitat Distribution

  • Native to New Zealand; widespread across the North Island and present throughout the South Island, Stewart Island/Rakiura, and the Chatham Islands/Rēkohu.
  • Two life-history types exist: sea-going (diadromous) fish that move between coastal seas, estuaries, and rivers, and landlocked lake populations — many of the latter were deliberately introduced to feed trout.
  • Particularly abundant in the Waikato River catchment; also found well inland in lower-gradient systems like the Whanganui and Manawatū rivers, up to 220 km from the coast.
  • Sensitive to warm water and pollutants — most reliably found in clean, cool, well-oxygenated water.

Key Locations

  • Waikato River catchment — the most consistently documented stronghold for common smelt in the North Island.
  • Whanganui and Manawatū rivers — lower-gradient systems where sea-run smelt penetrate well inland.
  • Estuaries and river mouths throughout the North Island, where migrating smelt concentrate and attract sea-run brown trout.
  • Various South Island lakes where smelt were introduced as trout forage — Canterbury coast waters may hold either common or Stokell's smelt.

Specific Spots

  • Schools hold near the surface in open water — look for them in mid-river runs and lake shallows rather than tight to the bottom or in heavy cover.
  • Estuaries and river mouths concentrate fish during sea-to-river migrations, making these transition zones productive for trout feeding on smelt.
  • In lakes, smelt schools often suspend over open water or near drop-offs, following drifting food and light conditions.

Common Smelt FAQ

Answers from onWater's species guide.

What are the best lures and bait for Common Smelt?

Small slim soft-plastics (50–75 mm) in silver or clear/glitter colours imitate the smelt's profile well and work for trout in estuaries and river mouths.

What flies work for Common Smelt?

Slim silver or white streamers, Rabbit Fur streamers, Marabou Smelt patterns, and small Clouser Minnows (all baitfish imitations), are the core flies when trout are keyed onto smelt in rivers, estuaries, and lake edges.

When is the best time to fish for Common Smelt?

Spring and summer (September–February), sea-run smelt return to rivers to spawn, concentrating fish and triggering active trout feeding in estuaries and lower river reaches.

How do you catch Common Smelt?

Most NZ anglers target smelt indirectly, by fishing smelt imitations to brown trout feeding on them in estuaries, river mouths, and lake margins. Shore-based fishing with light spinning gear or a fly rod along tidal reaches during the spring and summer smelt run is the most common approach.

What do Common Smelt eat?

Smelt feed on drifting zooplankton and small invertebrates near the surface, they're filter-and-drift feeders rather than hunters of the bottom. When targeting trout feeding on smelt, small silver streamer flies or slim soft-baits that mimic the smelt's slender profile are the go-to choice.

See it in the app

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