Fish identification archive / Longsnout Butterflyfish

Longsnout Butterflyfish

Prognathodes aculeatus

Fun facts for your next surface interval

A fin with a peak: The front dorsal spines form a triangular crest rather than a rounded fin.
Pocket-size butterfly: This butterflyfish reaches only about the length of a small index card.
A separate branch of the family: Its Brazilian sister species has a separate scientific identity.

Florida and local context

Broader Florida; no verified Lake Worth Lagoon checklist claim: Smithsonian species-distribution data include Florida Keys-area coordinates, for example [24.4418, -81.863]. These are database distribution records, not newly observed fish or a verified Lake Worth Lagoon checklist row.

Documented regional presence is not a guarantee of an encounter or a measure of how common this animal is at your dive site.

How to recognize this animal

This butterflyfish combines a projecting pointed snout with a tall triangular dorsal fin. The front of the upper body is yellow-orange, darkening to brown beneath the spiny dorsal. A slanting yellow-brown eye band and orange bar across the tail base complete the pattern. The lower body is pale and the pelvic and anal fins are yellow.

Size and life stages

At about 9.5 centimeters maximum, it is appreciably smaller than many familiar Florida butterflyfishes. Its long nose and high dorsal can exaggerate its apparent size in a close photograph. Use the whole silhouette, including the nearly vertical rear fin edges, rather than comparing a cropped head with a complete image of another species.

Habitat and where to look

Rocky and coral reefs provide habitat. Smithsonian reports records from one to 177 meters, most often at 15–55 meters. The upper end of that common interval already exceeds many recreational plans. A shallow encounter is possible, but the depth range should never be turned into a promise that a beginner reef dive will produce one.

Range and local context

The Smithsonian account places this western Atlantic species from North Carolina to Guyana, with a separate Brazilian sister species. Florida Keys-area distribution points corroborate Florida occurrence. The Lake Worth Lagoon checklist does not mark this species as verified; this profile therefore claims broader Florida presence, not a confirmed local checklist sighting or local abundance.

What is on the menu?

Its documented foods include attached worms, small bottom-dwelling crustaceans and echinoderm material. The narrow snout carries a small mouth with brush-like teeth, allowing precise picking rather than taking large bites. Watch where the mouth touches while maintaining distance; the prey may be too small or hidden to identify from an ordinary diver photograph.

Daily habits and behavior

FishBase describes this species as solitary or sometimes paired, and notes that it seeks refuge when approached. That makes a quiet, patient encounter more useful than pursuit. The tall front dorsal spines and deeply cut fin membranes create its crown-like outline when spread. A retreating fish may fold the fin, so apparent dorsal height alone should not settle an identification.

Mating and the next generation

The Smithsonian data identify pelagic eggs and larvae. This describes drifting early stages, not a nest guarded among the rocks. A local seasonal breeding schedule was not established in the reviewed sources. It would be misleading to convert a photographed pair, brighter orange color or a particular dive month into evidence of spawning.

Look-alikes and identification traps

Reef butterflyfish are larger and have a short snout with a strong dark wedge near the rear body. Bank butterflyfish have a different dark-band pattern. Brazilian Prognathodes brasiliensis is a separate sister species, not another Florida common name for this fish. A confident identification combines the nose, high spiny dorsal and orange-to-brown upper body.

Observe without disturbing

Approach slowly enough that the fish can retain access to its shelter. Do not reach behind coral or use a pointer to flush it out for the high-dorsal photograph. If it retreats, a wider contextual image is preferable to a forced close-up. Label an uncertain distant sighting conservatively rather than guessing from orange coloration alone.

Harvest, protection and eating safety

LIVE COLLECTION ONLY — NO FOOD HARVEST

Florida state and adjacent federal waters: limited licensed live collection may be lawful, with live landing/holding, life support, species size rules and bag/possession limits. No species-specific annual closed months are listed, but Blue Heron Bridge, Biscayne and other area closures override that allowance. This is not a blanket ban on lawful live collection or an eating recommendation. Listed-group collection is also prohibited in John Pennekamp.

This color is a qualified summary, not permission to collect or a guarantee that a particular catch is safe to eat. Read the current rules and health guidance below.

Restricted live collection only; no spearing; protected collection areas apply

Can it be hunted or harvested?

Longsnout Butterflyfish belongs to Florida's regulated marine-life category (butterflyfish family Chaetodontidae). Food harvest is not authorized by these live-only rules. Where collection is lawful, a saltwater license is required unless exempt; organisms must be landed and kept alive in an adequately sized continuously circulating, aerated or oxygenated system. Slot: 1–4 inches total length. Daily limit: five of this species within 20 total marine-life organisms per person. Two-day possession: ten of this species within 40 total. Recreational sale is prohibited.

Florida seasons and areas

No species-specific annual closed months are listed for this live-collection category. Florida marine-life requirements apply in state and adjacent federal waters on both Atlantic and Gulf coasts. Collection is prohibited inside the designated Blue Heron Bridge dive-site boundary, throughout Biscayne National Park and for this listed group in John Pennekamp Coral Reef State Park. The designated Western Dry Rocks area closes to all fishing April 1–July 31. In Biscayne National Park, the designated bonefish pre-spawning area closes to fishing and fish possession March 1–May 31; continuous transit with fish and gear properly stowed is allowed. Sanctuary, park and refuge zones may impose additional no-take or gear restrictions. These are area rules, not a claim that every Florida site is closed.

Can it be speared?

No. This species must remain alive, and spears are not an authorized recreational marine-life method. Where otherwise lawful, authorized gear is hand collection, permitted hand-held, drop or barrier nets, or a slurp gun. Quinaldine is prohibited. Protected-area rules override any general collection allowance.

Is it safe to eat?

Not a food-harvest species under the applicable live-only rules. Aquarium collection does not establish edibility or food safety. This identification page cannot establish that a particular catch is safe to eat. Consult current Florida DOH advice for the exact species and capture water, especially for pregnancy, breastfeeding and children. Do not borrow an advisory for a similarly named fish. Prompt chilling and proper cooking reduce some hazards, but cooking does not remove mercury or all marine toxins; absence of a named advisory is not a safety clearance.

Before you act: This recreational overview is not permission to collect or spear at your dive site. Confirm the species, date, management area, state or federal waters, gear, licenses and current local closures. Identification artwork cannot establish an identification or guarantee seafood safety.

Official rules and health guidance

Reviewed 2026-11-10. Rules and advisories can change; check the linked authorities before harvesting or eating.

Sources and review

Reviewed 2026-11-10.

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