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🌊 Marine Least Concern 🍽️ Edible 🌡️ Tropical

Blacknosed butterflyfish

Johnrandallia nigrirostris Gill, 1862
Max Length
20 cm
Max Weight
-
Lifespan
-
Trophic Level
3
Depth
6–40 m
Climate
Tropical
Resilience
High
Vulnerability
22.00/100
Typical Length
14 cm
Depth Zone
reef

📖 Overview

Often in large schools over coral and rocky reefs . Feed on algae, gastropods, and small crustaceans . Pick parasites from larger fishes like Paranthias colonus and Mulloides dentatus . Oviparous . Form pairs during breeding .

Scientific Name
Johnrandallia nigrirostris
Authority
Gill, 1862
Habitat
Marine
Climate
Tropical
Body Shape
Short and / or deep
IUCN Status
LC
Max Length
20 cm
Depth Range
6–40 m
Latitude
10°S – 40°N
Trophic Level
3
Resilience
High
Vulnerability
22.00/100
Salinity
30–40 ppt

🔬 Taxonomy

🐟 Physical Description

Dorsal spines (total): 11 - 12; Dorsal soft rays (total): 24 - 25; Anal spines: 3; Anal soft rays: 18 - 20. Body deep, compressed, and disk-shaped; dorsal profile of head steep and concave; snout pronounced; teeth very small and se in a comb-like band; base of pelvic spine with an axillary process; lateral line complete, extending over caudal peduncle; body yellowish; snout with a dark stain; eye bordered with black; posterior edge of operculum, base of pectoral fins, nape, and dorsal border (at base of dorsal fin) black .: short and / or deep; Cross section: compressed.

🌀 Behaviour

Johnrandallia nigrirostris aggregates in small groups. It is highly active during the day, during which time it feeds. At night, it shelters near to the reef's surface. This species is a kind of cleaner fish. It will remain at cleaning stations where infested fishes come to have various crustaceans and other ectoparasites removed.

🦐 Diet

Diet information for Blacknosed butterflyfish is currently being compiled.

🥚 Reproduction

Form pairs during breeding .

🌍 Habitat & Distribution

Marine; reef-associated; depth range 6 - 40 m , usually 6 - 12 m . Tropical; 40°N - 10°S, 120°W - 70°W

🌿 Ecology

Zone Preferences
🌊 Marine 🪸 Reef Associated
Trophic Level
3±0.44
🐠 Schooling
Food Items

algae, gastropods, and small crustaceans (Ref

📐 Morphometrics

Length–Weight Relationship: W = 0.02754 × L3.08 (TL)
Max TL
20cm
Dorsal Spines
12
Dorsal Rays
25
Anal Spines
3
Anal Rays
19

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Least Concern
Assessment Date
2009

📊 Population Risk & Fisheries

Population Resilience
High
Minimum doubling time
Fishing Vulnerability
22.00/100
Low vulnerability
Trophic Level
3
Predator
Body Shape
Short and / or deep
Climate Zone
Tropical
Latitude Range
40°N – 10°S
Described By
Gill, 1862

🍽️ Edibility & Flavour

"Blacknosed butterflyfish 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 18.6 g
Omega-3 (total) 114 mg

🔬 Mercury Safety

Mercury data for Blacknosed butterflyfish 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

🌐 Names & Taxonomy

Scientific Synonyms

Scientific Name Author Year Status
Chaethodon nigrirostris Gill 1862 Synonym
Chaetodon nigrirostris Gill 1862 Synonym
Heniochus nigrirostris Gill 1862 Synonym
Johnrandalia nigrirostris Gill 1862 Synonym
Pseudochaetodon nigrirostris Gill 1862 Synonym
Sarothrodus nigrirostris Gill 1862 Synonym

🗺️ Global Occurrence Map

Occurrence records from the Global Biodiversity Information Facility (GBIF) - 15 records indexed .

Occurrence density from GBIF View GBIF records ↗

👥 Community & Contribute

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View all observations for Blacknosed butterflyfish ↗
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