Banded Butterflyfish, Chaetodon striatus
Banded Butterflyfish, Chaetodon striatus. Underwater photographs taken in coastal waters of Bonaire, December 2019. Photographs courtesy of Bob Hillis, Ivins, Utah.
The Banded Butterflyfish, Chaetodon striatus, is a member of the Butterflyfish or Chaetodontidae Family, and is known in Mexico as mariposa rayada. The Butterflyfishes are reef fishes and some of the most colorful tropical fishes in the ocean. Globally there are ninty-three species of Butterflyfish in the genus Chaetodon, of which five are found in Mexican waters, four in the Atlantic and one in the Pacific Ocean.
The Banded Butterflyfish is a small flat fish that has a shaped like a strongly compressed deep oval disc. They are silver white in color with thin black chevron black lines on the body with 4 wide black bars, one through the eye to the nape, one behind the pectoral fins, one from the front of the soft dorsal to the anal fin, and one from soft dorsal to across the caudal peduncle to the anal fin base. They also have a broad black stripe at the base of the anal and soft dorsal fins, a broad black bar near the margin of the caudal fin and a broad black band near the margin of the pectoral fins. The juveniles are similar in color but lack the bar on the caudal fin and have a large ringed black ocellus at the rear of their dorsal fin. Their head has a short, pointed snout and a sloping forehead with a strongly concave upper profile with a small protractile mouth equipped with comb-like teeth set in bands of 9 or 10 rows on each jaw. The rear margins of the anal and dorsal fins are bluntly angular. Their anal fin has 3 spines, with the second spine longer than the third, and 16 or 17 ray; their caudal fin is rounded; and, their dorsal fin has 12 prominent spines and 19 to 21 rays. Their body is covered with large rough scales. Their lateral line is incomplete with a high arch.
The Banded Butterflyfish inhabits rocky and coral reefs at depths up to 110 m (360 feet) and reach a maximum of 16 cm (6.3 inches) in length. They are a diurnal species that is active during the day feeding on feed on algae and benthic invertebrates. Adults may form plankton feeding aggregations of up to twenty individuals, and occasionally clean other reef fishes which join the group, such as grunts, parrotfishes and surgeonfishes. The juveniles are found closer to shore within seagrass beds. For protection they rely on their markings for protection and utilize flight as their first line of defense and if cornered rely on their long sharp and prominent dorsal fin spines for protection. At night they take shelter to avoid predation by moray eels, various sharks and larger fishes. They are strong swimmers capable of maneuvering through coral reefs with ease by swimming sideways or upside down. Reproduction is oviparous in monogamous pairs that mate for life that become highly territorial. Each female releases between 3,000 and 4,000 small pelagic eggs, that hatch within a day. The larvae are also pelagic that travel great distances in the oceanic currents. The vast majority of young fish are consumed by other predators.
The adult Banded Butterflyfish, due to its markings is a straightforward identification. The juveniles however, are easily confused with the Foureye Butterflyfish, Chaetodon capistratus (2 bars and 2 black spots on the body; no ocellus).
The Banded Butterflyfish is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the east coast of the Yucatán Peninsula in the Caribbean.
From a conservation perspective the Banded Butterflyfish is currently considered to be of Least Concern with stable widely distributed populations. The major concern at present for their long-term survival relates to habitat degradation and loss of the coral reefs in which they reside. They are not utilized as a human food fish. They are utilized by the aquarium trade but are difficult to manage. They are a focus fish of underwater divers and in general are not unfriendly but will flee if approached.