New 🐟 Mercury Safety Guide & Omega-3 Rankings Updated for 2026. View Omega-3 Rankings →

Diadromous Vulnerable 🍽️ Edible 🎣 Game Fish 🌡️ Subtropical

Giant kokopu

Galaxias argenteus Gmelin, 1789
Max Length
-
Max Weight
-
Lifespan
-
Trophic Level
3.2
Depth
-
Climate
Subtropical
Resilience
High
Vulnerability
24.00/100
Typical Length
-
Depth Zone
demersal

📖 Overview

Giant kokopu (Galaxias argenteus), first described by Gmelin, 1789 is a fish in the family Galaxiidae (order Galaxiiformes). It is diadromous, migrating between freshwater and marine environments during its life cycle. It occurs in Subtropical waters. It is broadly omnivorous, taking invertebrates, plant matter, and detritus. On the IUCN Red List, it is classified as Vulnerable.The species is important as a food fish and valued as a game and sport species. As a member of the Galaxiidae, it shares life-history and morphological traits with its relatives in the group.

Scientific Name
Galaxias argenteus
Authority
Gmelin, 1789
Habitat
Diadromous
Climate
Subtropical
IUCN Status
VU
Trophic Level
3.2
Resilience
High
Vulnerability
24.00/100
Migration
Amphidromous
Salinity
30–40 ppt

🐟 Physical Description

Physical description for Giant kokopu is currently being compiled.

🌀 Behaviour

Behavioural data for Giant kokopu is currently being reviewed.

🦐 Diet

aquatic invertebrates
small fish
algae
detritus

🥚 Reproduction

🐣 Oviparous 📦 Batch Spawner
Spawning Season
spring
Spawn Location
Substrate
Fertilization
External

🌍 Habitat & Distribution

Marine; freshwater; brackish; demersal; amphidromous . Subtropical; 34°S - 47°S Southwest Pacific: endemic to New Zealand.

🌿 Ecology

Zone Preferences
🌊 Marine 💧 Freshwater 🌿 Brackish ⬇️ Benthic
Migration
Amphidromous
Trophic Level
3.2±0.5

📐 Morphometrics

Length–Weight Relationship: W = 0.01122 × L3.04 (TL)

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Vulnerable
Assessment Date
2014

📊 Population Risk & Fisheries

Population Resilience
High
Minimum doubling time
Fishing Vulnerability
24.00/100
Low vulnerability
Trophic Level
3.2
Predator
Climate Zone
Subtropical
Described By
Gmelin, 1789

🎣 Angling Guide

Difficulty
Beginner
Fight Rating
strong pulls with head-shakes
Best Seasons
spring,summer,fall
Best Time
incoming tide, dawn and dusk
Line Weight
15-30
Rod Type
medium-heavy spinning
Hook Size
2/0-5/0
Catch & Release
✓ Recommended
Best Months
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Techniques
bottom fishing popping cork soft plastics live bait
Bait & Lures
live shrimp cut mullet soft plastic paddle-tails popping corks
Recommended Tackle
  • medium-heavy 7ft spinning rod
  • 30-50 lb braid
  • fluorocarbon leader
Where to Find Them
  • grass flats
  • oyster bars
  • marsh drains
  • deeper channel edges
Tips & Tricks
Popping cork technique attracts fish from distance. Fish moving tides.
Catch & Release Tips

Use barbless hooks, minimise air exposure, and revive fish head-first in current before release.

Regulations Summary

⚠️ Slot limits protect breeding-size fish. Verify daily bag limits.

🍽️ Edibility & Flavour

"Galaxias Argenteus is an edible species."

✗ Not for Raw
✓ Fresh Indicators
  • Clear, bright eyes — cloudy eyes indicate age
  • Firm flesh that springs back when pressed
  • Fresh ocean smell, never strong or ammonia-like
  • Bright red or pink gills, not grey or brown
  • Shiny, moist skin with scales tightly attached
✗ Avoid If
  • Cloudy or sunken eyes
  • Strong fishy or ammonia odour
  • Soft, mushy flesh that doesn't spring back
  • Discoloured or dry flesh
Best Cooking Methods
Baking Grilling Pan-frying

⚡ Nutrition

Detailed nutritional data for Giant kokopu is currently being compiled from USDA FoodData Central.

🔬 Mercury Safety

Mercury data for Giant kokopu has not yet been assigned. Please consult FDA/EPA guidance for general seafood safety advice.

🌿 Sustainability

Best Choice
Healthy stocks, low impact
Good Alternative
Well-managed, minor concerns
Use Caution
Check sourcing and season
Avoid
Overfished or high impact

🔬 Full Nutritional Profile

Per 100g - Raw, per 100g - Source: USDA FoodData Central templates (generic fish average)

Proximate Composition
Energy125 kcal
Moisture75 %
Protein20 %
Total Fat4 %
Ash1.3 %
Fatty Acids (g)
Saturated Fat1 g
Monounsaturated Fat1.2 g
Polyunsaturated Fat1.5 g
Omega-3 Total1 g
EPA0.3 g
DHA0.5 g
Omega-6 Total0.3 g
Key Minerals & Vitamins
Calcium20 mg
Iron0.7 mg
Magnesium30 mg
Phosphorus220 mg
Potassium380 mg
Sodium55 mg
Zinc0.5 mg
Selenium32 µg
Vitamin B122 µg

📊 Population Dynamics

Year Region Index Notes
- - -

👥 Community & Contribute

Aquareap Community Observations
0 Observations logged on Aquareap

No observations yet - be the first to log one!

View all observations for Giant kokopu ↗
Suggest an Edit

Spotted incorrect or outdated data? Submit a correction and our editorial team will review it. Approved edits go live within 48 hours.

Link to a scientific paper, FishBase, or other authoritative source
Report an Issue

Found a factual error, broken data, or inappropriate content? Let us know and we will investigate promptly.