Blacknosed butterflyfish
📖 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 .
🔬 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
🥚 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
algae, gastropods, and small crustaceans (Ref
📐 Morphometrics
🌡️ Water Parameters & Tolerance
🛡️ Conservation Assessment
📊 Population Risk & Fisheries
🍽️ Edibility & Flavour
"Blacknosed butterflyfish is an edible species."
- 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
- Cloudy or sunken eyes
- Strong fishy or ammonia odour
- Soft, mushy flesh that doesn't spring back
- Discoloured or dry flesh
⚡ 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
🔬 Full Nutritional Profile
Per 100g - Raw, per 100g - Source: USDA FoodData Central templates (generic fish average)
📊 Population Dynamics
| Year | Region | Index | Notes |
|---|---|---|---|
| - | - | - |
🌐 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 |
🦠 Common Diseases
The following diseases are known to affect Blacknosed butterflyfish.
🔍 Similar Species
🗺️ Global Occurrence Map
Occurrence records from the Global Biodiversity Information Facility (GBIF) - 15 records indexed .
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