Chaetodon daedalma
A metallic black butterflyfish endemic to Japanese waters.
The wrought-iron butterflyfish, *Chaetodon daedalma*, is a marine ray-finned fish in the family Chaetodontidae. Its most striking feature is its mostly metallic black body, a rare color for butterflyfish, which are typically far more vivid. Yellow edges mark the dorsal, anal, and caudal fins, while the scales have pale yellow centers and broad black borders, creating a cross-hatched or net-like pattern. This species reaches a maximum total length of 15 centimeters (5.9 inches).
Endemic to Japan, it appears on the main islands south of Sagami Bay, as well as the Ryukyu, Ogasawara, and Izu Islands. It inhabits clear, outer waters, usually deeper than 10 meters (33 feet), over rocky reefs. Adults are social and nomadic, forming schools of more than 10 individuals that roam widely. They graze on algae and benthic invertebrates like fanworms, hydroids, gastropods, barnacles, and tunicates. Sometimes huge numbers gather to feed in a tight, undulating formation called a "wrought-iron ball," thought to be a defense tactic. This species is oviparous, with males and females pairing for breeding.
First formally described in 1902 by American ichthyologists David Starr Jordan and Henry Weed Fowler, the type locality is Naha, Okinawa Island in the Ryukyu Islands. The specific name *daedalma* refers to a style of artistic embroidery, alluding to the fish’s pattern.
Outside Japan, *Chaetodon daedalma* is uncommon in the aquarium trade due to its restricted range and preference for cooler water than related species. When exported, it commands a high price.
- Maximum total length
- 15 cm (5.9 in)
- Native region
- western Pacific Ocean near central and southern Japan
- Depth range
- normally in excess of 10 m (33 ft)
- School size
- normally more than 10 individuals
- Type locality
- Naha, Okinawa Island, Ryukyu Islands
- Described by
- David Starr Jordan and Henry Weed Fowler
- Year described
- 1902
Lore & Background
Chaetodon daedalma was first formally described in 1902 by American ichthyologists David Starr Jordan and Henry Weed Fowler, with the type locality given as Naha, Okinawa Island in the Ryukyu Islands. The specific name daedalma means a style of artistic embroidery, referring to the patterning shown by this species. The body has markings resembling a cross-hatch pattern, and the scales have pale yellow centers with broad black margins, forming a lattice or netted pattern. The largely black coloration is very unusual for a butterflyfish.
This species is endemic to Japan, found on the main islands south of Sagami Bay, as well as the Ryukyu Islands, the Ogasawara Islands, and the Izu Islands. It inhabits clear, outer waters at depths normally exceeding 10 meters. Adults are sociable and normally found in schools numbering more than 10 individuals; they are nomadic and range over a wide area. They prefer rocky reefs where they graze on algae and benthic invertebrates, including fanworms, hydroids, gastropods, barnacles, and tunicates. Sometimes these fish congregate in huge numbers, forming a tight, undulating formation called a 'wrought-iron ball,' thought to be a defensive strategy.
Reader's Guide
Chaetodon daedalma is uncommon in the fishkeeping trade outside Japan due to its restricted distribution and its preference for cooler conditions than related species. When exported, it commands a high price. Its unusual metallic black coloration, which is rare among butterflyfish, makes it a distinctive species. The species is oviparous, with males and females forming pairs for breeding. The formation of a 'wrought-iron ball' by large congregations is a notable behavioral trait, interpreted as a defensive strategy. The species' scientific name, derived from a style of artistic embroidery, directly references its unique lattice-like scale pattern.
Did You Know?
- Chaetodon daedalma is mainly metallic black, an unusual color for a butterflyfish.
- It was first described in 1902 from a specimen collected at Naha, Okinawa Island.
- Schools sometimes form a tight, undulating 'wrought-iron ball' thought to be a defensive strategy.
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