Blackpatch Triggerfish

Rhinecanthus Verrucosus
Blackpatch Triggerfish - Marinewise © 2025 MarineWise

Quick Facts

Scientific name Rhinecanthus Verrucosus
Other names Blackbelly Picassofish, Blackbelly Triggerfish, Blackblotch Triggerfish
Size Up to 23 cm (9.05 in)
Weight Up to 1 kg (2.2 lb)

Distribution

Habitat & AU Distribution Coastal waters amongst lagoons & reef flats in areas of rubble & algae growth
Depth Range Up to 20 m (66 ft)
Blackpatch Triggerfish Distribution

Interesting Info

  • The Blackpatch Triggerfish is found across the Indo-Pacific, including northern Australia, where it lives on the Great Barrier Reef, Coral Sea, and reefs of Western Australia.
  • It gets its name from the distinct dark patch found just behind its pectoral fin — a feature that helps distinguish it from its close relatives.
  • This species is smaller than the big triggerfish we’ve covered, usually reaching around 23 cm (9 in) in length.
  • Its body is oval and laterally compressed, coloured light brown to cream with bold black stripes and bright blue and yellow highlights around the face.
  • Juveniles are often more pale, with their markings becoming bolder as they mature.
  • Like all triggerfish, they have a dorsal trigger spine which they use to wedge themselves into cracks when threatened — making them almost impossible to pull out.
  • They are most often seen in shallow lagoons, sandy reef flats, and seaward reef slopes, generally from the surface down to about 20 m (66 ft).
  • Blackpatch Triggerfish are omnivores, feeding on a mix of small crabs, molluscs, sea urchins, worms, and algae. Their strong teeth allow them to crunch through hard shells.
  • Breeding occurs in shallow sandy patches where pairs build nests, and both males and females aggressively guard their eggs until hatching.
  • Like their relatives, they can be territorial during nesting season, chasing away intruders much larger than themselves, including snorkellers and divers.
  • In the reef ecosystem, they play an important role as small predators, helping to keep populations of invertebrates and algae balanced.
  • They usually live for around 7–10 years, though their exact maximum lifespan in the wild isn’t well studied.
Species Interaction

Snorkelling & Diving

Blackpatch Triggerfish are a favourite among snorkellers because of their bold colours and quirky behaviour. They are often seen in pairs or small groups patrolling sandy reef flats, but they can be territorial and may dart towards intruders during nesting season — so it’s best to admire them from a respectful distance.

Scientific Classification

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Tetraodontiformes

Family: Balistidae

Genus: Rhinecanthus

Species: Rhinecanthus Verrucosus

Conservation Status

The Blackpatch Triggerfish is listed as Least Concern by the IUCN. It is widespread across the Indo-Pacific and remains common in healthy reef systems, though like all reef fish it relies on the continued health of coral habitats.

Fish Taste Quality

Blackpatch Triggerfish is edible and occasionally eaten in Pacific regions but not a targeted food fish in Australia. As with other reef fish, there is some risk of ciguatera poisoning.

Taste Rating: 1/5

How to catch
Blackpatch Triggerfish

Catch Difficulty: Easy

Tackle: Patternoster Rig, Running Sinker Rig

Bait: Crab, Fresh cut flesh baits, Octopus, Prawns, Shellfish, Squid, Worms

Technique: Keep bait close to the reef/structure

Popularity: Not targeted - Bycatch

Recreational Viewing
- Snorkeling & Scuba

Finding: Easy

Temperament: Semi-Aggressive

Location: Inner Reef, Outer Reef, Lagoon

Danger: None