Merten's Butterflyfish (Chaetodon mertensii)

Quick facts

Appearance

Merten's Butterflyfish is a deep-bodied, disc-shaped fish with predominantly yellow coloration on the head, body, and dorsal fin. A distinctive black band runs from the nape through the eye, and the posterior body is dusky blue-gray. The pectoral and anal fins display yellow with darker margins, and the caudal fin is yellow with dark edges.

Diet and feeding

In captivity, offer a varied diet of small meaty foods including mysis shrimp, brine shrimp, and finely chopped seafood, supplemented with high-quality marine flakes and small pellets. Include occasional vegetable matter or spirulina-enriched foods.

Difficulty and care for the Merten's Butterflyfish

Merten's Butterflyfish is moderately challenging for hobbyists due to its requirement for excellent water quality and consistent feeding regimes. Acclimation can be slow, and the species may initially refuse food in captivity, necessitating patience and specialized care.

Common health issues

Ich (Cryptocaryon irritans), Marine velvet (Oodinium ocellatum), Parasitic infections, Loss of appetite during acclimation

Origin and habitat

Indo-Pacific from the Red Sea and East Africa through Indonesia to the Great Barrier Reef and Samoa, typically found in deeper outer reef habitats and drop-offs at depths of 20–60 meters.