# Hawaiian Convict Surgeonfish (*acanthurus sandvicensis*) The Hawaiian Convict Surgeonfish, known locally in Hawaii as "manini," is a vibrant and highly social reef fish. Renowned for its bold, vertical stripes resembling a traditional prisoner's uniform, this striking species plays a vital role in maintaining the health of Hawaiian coral reefs. They are often seen in massive, synchronized schools, numbering in the hundreds, as they sweep across shallow reef flats to graze. This schooling behavior is not just social; it is a tactical strategy to overwhelm territorial damselfishes that guard their own private algae gardens. As an endemic species to the Hawaiian Islands, the manini holds cultural significance and is a beloved sight for snorkelers and divers alike. Their constant activity and ecological contribution as primary herbivores make them an essential and delightful species to observe in the wild. - **Category:** [Fish](https://www.snappit.app/explore/categories/fish) - **Rarity:** Common - **Danger:** 1/5 · Very low - **Snaps:** 3 - **Habitat:** Found in shallow coral reefs, rocky shorelines, and exposed tide pools throughout the Hawaiian Archipelago. ![Hawaiian Convict Surgeonfish](https://inaturalist-open-data.s3.amazonaws.com/photos/1573822/medium.jpg) Photo: Brocken Inaglory, CC BY-SA 4.0 · [iNaturalist](https://www.inaturalist.org/photos/1573822) ## Appearance This species features a compressed, oval-shaped body that is predominantly a pale greenish-yellow or silvery-white, accented by six distinct, vertical black bars running down its sides. It has a sharp, spine-like "scalpel" near the base of its tail which is used for defense. The head is rounded with a small, downturned mouth perfectly adapted for scraping algae from rocks, and they typically grow to a length of about 12 to 25 centimeters. ## Taxonomy - **Kingdom:** Animalia - **Phylum:** Chordata - **Class:** Actinopterygii - **Order:** Acanthuriformes - **Family:** Acanthuridae - **Genus:** Acanthurus ## Interesting facts - During spawning cycles, huge aggregations form at dusk to release gametes directly into the water column, utilizing the cover of darkness to protect their eggs. - Its Hawaiian name, 'manini', is so common that it has entered local slang to mean 'small' or 'insignificant', referencing the fish's small size compared to larger game fish. - They possess a sharp, venomous spine on their tail base that can cause painful wounds if handled carelessly. ## Special abilities - **Tail Scalpel Defense:** Possesses sharp, modified scales on either side of the caudal peduncle that can fold out like scalpels to deter predators. - **Swarm Grazing:** Schools in large numbers to overwhelm aggressive, territorial damselfishes and safely feed in their heavily defended algal lawns. - **Rapid Color Shifts:** Capably fades or intensifies its dark vertical stripes depending on stress levels, social interactions, or environmental background. ## Measurements & details - **Length:** 12-25 cm - **Weight:** 0.1-0.4 kg - **Lifespan:** 5-15 years - **Speed:** 15 km/h - **Clutch Size:** 10000-100000 - **Incubation:** 1-2 days ## Diet & Feeding Feeds constantly during the day on fine filamentous and turf algae growing on coral rubble and rocks. - **Age differences:** Larvae and post-larvae feed on plankton before transitioning to a strictly herbivorous diet as they settle onto the reef. - **Primary Foods:** Filamentous algae, Turf algae, Microalgae, Detritus - **Foraging Method:** Grazing ## Ecological connections - **Competitor:** [Yellow Tang](https://www.snappit.app/explore/yellow-tang) (*Zebrasoma flavescens*) — Competes for filamentous algae on shallow reefs. - **Eaten by:** Whitetip Reef Shark (*Triaenodon obesus*) — Preys on adult surgeonfish sheltering in reef crevices at night. - **Mutualism:** Hawaiian Cleaner Wrasse (*Labroides phthirophagus*) — Removes ectoparasites and dead skin from the surgeonfish's body at cleaning stations. ## Safety **Danger:** 1/5 · Very low No special safety notes yet. ## Frequently Asked Questions ### How to identify Hawaiian Convict Surgeonfish? Look at body shape, where the fins sit and their outline, mouth position, stripes and spots. Young fish and breeding adults can wear different patterns, and aquarium color varieties can look nothing like wild fish. Fish Identifier: upload a photo and compare the visible details. ### How long is Hawaiian Convict Surgeonfish? 12-25 cm ### How much does Hawaiian Convict Surgeonfish weigh? 0.1-0.4 kg ### How long does Hawaiian Convict Surgeonfish live? 5-15 years ### How fast can Hawaiian Convict Surgeonfish move? 15 km/h ### What does Hawaiian Convict Surgeonfish eat? Feeds constantly during the day on fine filamentous and turf algae growing on coral rubble and rocks. ### Where is Hawaiian Convict Surgeonfish usually found? Found in shallow coral reefs, rocky shorelines, and exposed tide pools throughout the Hawaiian Archipelago. ### How does Hawaiian Convict Surgeonfish hunt? Grazing ## Where to spot - [Kahaluu Bay](https://www.snappit.app/guides/places/kahaluu-bay) — Hawaii, US · Historic District - [Lahaina Historic District](https://www.snappit.app/guides/places/lahaina-historic-district) — US · Historic District - [Waimea Valley](https://www.snappit.app/guides/places/waimea-valley) — Hawaii, US · Botanical Garden - [Koko Crater Botanical Garden](https://www.snappit.app/guides/places/koko-crater-botanical-garden) — Hawaii, US · Botanical Garden - [McBryde Garden](https://www.snappit.app/guides/places/mcbryde-garden) — Hawaii, US · Botanical Garden - [Moir Gardens](https://www.snappit.app/guides/places/moir-gardens) — Hawaii, US · Botanical Garden [View all places to see Hawaiian Convict Surgeonfish](https://www.snappit.app/guides/where-to-see/hawaiian-convict-surgeonfish) ## More Fish - [Rainbow Trout](https://www.snappit.app/explore/rainbow-trout) (*Oncorhynchus mykiss*) - [Brown Trout](https://www.snappit.app/explore/brown-trout) (*Salmo trutta*) - [Brook Trout](https://www.snappit.app/explore/brook-trout) (*Salvelinus fontinalis*) - [Lake Trout](https://www.snappit.app/explore/lake-trout) (*Salvelinus namaycush*) --- Source: [Hawaiian Convict Surgeonfish Facts — Snappit](https://www.snappit.app/explore/hawaiian-convict-surgeonfish)