Longnose Butterfly - Marcella

Description

The Longnose Butterflyfish has a compact, laterally compressed body with a distinctive long, pointed snout adapted for foraging small invertebrates from crevices. Its body displays a dark brown to black base color with bright yellow markings along the dorsal and caudal regions, and contrasting pale patches along the mid-body.

Adults reach a maximum size of 12–15 cm (4.5–6 inches). Its elegant elongated snout and subtle coloration patterns give it a refined, understated beauty compared to more flamboyant butterflyfish species.

Aquarium Requirements

Minimum Tank Size: 180–250 litres (50–65 US gallons)

Temperature: 24–27 °C (75–81 °F)

pH: 8.1–8.4

Specific Gravity (Salinity): 1.020–1.025

Alkalinity: 8–12 dKH

Ammonia & Nitrite: 0 ppm

Nitrate:< 10 ppm

Aquascape and Environment:
Provide a mature, well-established aquarium with abundant live rock, caves, and crevices to mimic its natural reef slope habitat. The Longnose Butterflyfish is a shy, cryptic species that relies on hiding places for security and foraging. Moderate water flow and high water quality are essential to maintain health and activity.

Diet and Feeding

Prognathodes marcellae is a carnivorous species that feeds primarily on small benthic invertebrates and zooplankton in the wild. In captivity, it can adapt to prepared and frozen foods but may require patience during acclimation.

Recommended Foods:

• Frozen mysis shrimp, finely chopped krill, and brine shrimp

• High-quality marine carnivore flakes and pellets

• Live foods such as blackworms or copepods to stimulate natural foraging

• Occasional enrichment with sponge-based foods

Feed 2–3 times daily in small portions, offering food near hiding spots to encourage confident feeding.

Temperament and Compatibility

The Longnose Butterflyfish is peaceful but shy, spending much of its time in and around rockwork. It is generally non-aggressive toward other species but may show territorial behaviour toward conspecifics in small aquariums.

Suitable Tankmates:

• Peaceful reef fish such as gobies, blennies, small wrasses, and anthias

• Invertebrates like shrimp, snails, and soft corals

Avoid:

• Aggressive or fast-feeding species that may outcompete it for food

• Other Prognathodes species unless housed in a very large, well-structured tank

Reef Compatibility

⚠️ Mostly Reef Safe

The Longnose Butterflyfish is generally reef safe but may occasionally nip at sessile invertebrates like tube worms. Its shy and cryptic nature usually limits interactions with corals, making it suitable for mature reef systems with plenty of hiding spots.

Additional Information

Maximum Size: 12–15 cm (4.5–6 inches)
Lifespan: 8–10 years in captivity (with proper care)
Difficulty Level: Moderate (requires mature tank and patient acclimation)
Natural Behaviour: Shy, crevice-dwelling, cryptic forager; active mostly during the day
Origin: Western Atlantic – Caribbean, southern Florida, Bahamas
Colouration: Dark brown to black body with bright yellow markings; pale mid-body patches; elongated pointed snout

Summary

The Longnose Butterflyfish (Prognathodes marcellae) is a rare and elegant species, admired for its elongated snout, subtle coloration, and cryptic reef-dwelling behaviour. Peaceful, shy, and moderately demanding, it thrives in mature aquariums with abundant live rock, crevices, and high-quality diets. Ideal for advanced aquarists, this butterflyfish adds a unique and understated charm to a FOWLR or well-established reef system.