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

Diadromous Least Concern 🍽️ Edible 🌡️ Tropical

Longtail Silverbiddy

Gerres longirostris Lacepède, 1801
Max Length
44.5 cm
Max Weight
Lifespan
9 yrs
Trophic Level
3.5
Depth
0–50 m
Climate
Tropical
Resilience
Medium
Vulnerability
30.00/100
Typical Length
20 cm
Depth Zone
reef

📖 Overview

Adults often in clear coastal waters up to about 50 m depth; juveniles often in estuaries or lagoons influenced by fresh water ; they prefer shallow waters over sandy bottoms, from coral reefs to brackish waters . Fry about 10 cm in length enter the estuaries and stay until they reach maturity . Occur singly or in groups . Feed on small bottom invertebrates . In the Gilberts, the species forms spawning aggregations for a few days around the new moon . Sold fresh in markets; processed into fishmeal. Also taken with stake-nets .

Scientific Name
Gerres longirostris
Authority
Lacepède, 1801
Habitat
Diadromous
Climate
Tropical
Body Shape
Fusiform / normal
IUCN Status
LC
Max Length
44.5 cm
Lifespan
9 years
Depth Range
0–50 m
Latitude
36°S – 32°N
Trophic Level
3.5
Resilience
Medium
Vulnerability
30.00/100
Migration
Amphidromous
Salinity
30–40 ppt

🔬 Taxonomy

🐟 Physical Description

Dorsal spines (total): 9; Dorsal soft rays (total): 10; Anal spines: 3; Anal soft rays: 7. Live specimens' head and trunk sides olive-green above, becoming silvery below; snout region blackish dorsally; dorsal fin membrane with faint black blotches or small spots at each spine and ray, just above edge of scaly basal sheath, silvery anteriorly on 1st-5th dorsal spine, grading to hyaline on spinous and soft dorsal fin; anal fin scaly basal sheath silver; distal part of pelvic fin between 1st-5th soft rays often white or hyaline for 1/5-1/3 of ray length, other parts hyaline or slightly yellowish; pectoral and anal fins hyaline. Caudal fin dusky with broad darker margin posteriorly which may be indistinct in old or poorly preserved specimens; ventral edge of lower caudal fin lobe white or bluish-white. Generally, body with prominent dark stripes along scale rows above lateral line (distinct in preserved specimens); 4-9 somewhat oblique dusky bars or columns of ovoid dark spots immediately below lateral line in specimens over 10 cm SL (dusky bars on less than 10 cm) but more apparent in preserved or stressed individuals. Scales between 5th dorsal fin spine base and lateral line 5-6.5 (modally 5.5). Upper jaw extending vertically beyond anteriormost margin of dermal eye opening, sometimes reaching to vertical at anterior margin of pupil. Second dorsal fin spine longest, 17-25% SL . Pre-opercle lower flange scaled. Body depth max 2.3-2.8 in SL. Pectoral fins reaches to or beyond level of anal-fin origin; caudal fin forked deeply . Pelvic fin of Red Sea specimens solid yellow with a narrow white distal margin; anal fin with a yellow tinge between the first rays; pectoral fin base with a dark brown spot (Horst Moosleitner, personal communication, homosub@aon.at). Examination of the meristic and morphometric data of the syntypes of G. lineolatus and G. rueppellii, and holotype of G. darnleyense showed all these are subadult or young specimens of G. longirostris .: fusiform / normal; Cross section: compressed.

🌀 Behaviour

Behavioural data for Longtail Silverbiddy is currently being reviewed.

🦐 Diet

Diet information for Longtail Silverbiddy is currently being compiled.

🥚 Reproduction

Size at Maturity
20.6cm TL

🌍 Habitat & Distribution

Marine; freshwater; brackish; reef-associated; amphidromous ; depth range 0 - 50 m . Tropical; 32°N - 36°S, 24°E - 170°W South Africa to the Marquesas Islands, north to the Ryukyu Islands, south to Australia.

🌿 Ecology

Zone Preferences
🌊 Marine 💧 Freshwater 🌿 Brackish 🪸 Reef Associated
Migration
Amphidromous
Trophic Level
3.5±0.34
Food Items

small bottom invertebrates (Ref

📐 Morphometrics

Length–Weight Relationship: W = 0.01072 × L3.05 (TL)
Max TL
44.5cm
Dorsal Spines
9
Dorsal Rays
10
Anal Spines
3
Anal Rays
7

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Least Concern
Assessment Date
2015

📊 Population Risk & Fisheries

Population Resilience
Medium
Minimum doubling time
Fishing Vulnerability
30.00/100
Low vulnerability
Trophic Level
3.5
Predator
Body Shape
Fusiform / normal
Climate Zone
Tropical
Latitude Range
32°N – 36°S
Described By
Lacepède, 1801

🍽️ Edibility & Flavour

"Longtail Silverbiddy 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

Per 100g cooked — Source: USDA FoodData Central

Nutrient Amount
Protein 19.5 g
Omega-3 (total) 146 mg

🔬 Mercury Safety

Mercury data for Longtail Silverbiddy 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

👥 Community & Contribute

Aquareap Community Observations
0 Observations logged on Aquareap

No observations yet — be the first to log one!

View all observations for Longtail Silverbiddy ↗
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.