Spotfin Butterflyfish

Chaetodon ocellatus



Kingdom Animalia

Phylum Chordata

Class Actinopterygii

Order Perciformes

Family Chaetodontidae

Fast Facts

English common names: Butterbun, Common Butterflyfish, Katy, School Mistress,

Spanish common names: Parche Ocelado Amarillo, Mariposa, Isabelita de lo Alto

Diet: Coral, Tubeworms, Small invertebrates; Zoantharians, Polychaete worms, Gorgonians, Tunicates

Body type: Compressed

Maximum size: about 6-8 inches (15-20 cm).

Life History/ Ecology


Spotfin Butterflyfish’s habitats are from the Atlantic Ocean and the Gulf of Mexico This is predominantly a shallow coral reef species (2.Anonymous). Juveniles reside in sea grass beds. Adults are commonly found in pairs, or in small groups of 4 to 5.  They swim and feed over bare, sandy bottoms. This type of feeding differs the Spotfin from other species of butterflyfish that mainly feed in shallow reef areas (3.Anonymous).

Resources/ Behavior

The Spotfin Butterflyfish uses defense as a main resources. It has very sharp fin rays, which are extended when it feels threatened.

It often chooses a small coral head or crevice in which it will spend most of its life, and if need be, quickly dart out of sight at any sign of danger. It is very curious, and will come out of its hiding place to investigate after it has been threatened, which makes them easy for to catch (1.Anonymous).

The eyespot near the tail and the eye stripe on the head are also a vital form of protection (1.Anonymous). Juveniles have a second spot on their anal fin that disappears as they mature (2.Anonymous). By hiding its real eye with a black strip and having a dot “false eye” near the tail confuses predators. A predator normally attacks the head of a fish to have a better chance of a successful catch, will attack the wrong end, enabling the Spotfin butterflyfish to make a quick escape to safety (1.Anonymous).

They are daytime feeders. They use vision to find their prey. Pairs communicate visually. If a pair becomes separated, one may swim upwards in a display so that the other can locate it (Helfman, Collete, and Facey, 1997; Moyle and Cech, 2000).


Spotfin Butterflyfish spawn in the summer (1.Anonymous). They spawn at early dusk and usually only pairs are involved. During the reef courtship the fish chase each other around, doing headstands and lateral displays. The pair circle each other until one swims off while the other follows.

Even though observation of Spotfin spawning hasn’t been made, it is thought that they spawn all year, and early summer is the time period where they reach their peaking point. Within a day of fertilization, the eggs hatch into minute larvae (3.Anonymous). The larvae are oceanic drifters, which explain why they are probably the most common tropical fish in New England (1.Anonymous). At night the larvae settle out of the plankton, after reaching around 20mm, and settle onto a substrate. In the morning the larvae transform into juveniles. Juveniles can be identifies as miniature butterflyfish. Shallow water predators eat the majority of the juveniles. The juveniles who remain alive quickly find crevices, where they stay until they become adults (3.Anonymous).

Economic/ Ecological Services

The Spotfin Butterflyfish species is very abundant. They are well liked by humans. Therefore, they are popular in the aquariums trade (3.Anonymous).

Recent Research

The Spotfin Butterflyfish is one of seven Chaetodon species in the western North Atlantic is reported from temperate waters, quite unlike most other chaetodontids, which are only found at tropical and subtropical latitudes. This study conducted by Richard S. McBride and Kenneth W. Able describes the ecology of these species at temperate latitudes and tests the hypothesis that these individuals are expatriates, withdrew from their native regions that die from hypothermal conditions at the start of winter. Over the course of four years, 1990-1993, they collected fish with dip nets and bottom traps, in a New Jersey estuary. They concluded that the Spotfin Butterflyfish (C. ocellatus), the most abundant species out of the seven, arrived as pelagic juveniles (or tholichthys stage) as early as July, ranging from sizes of 17-22 mm total length. It settled as small as 18 mm, grew about 0.1-0.2 mm d−1, and reached a maximum size of 77 mm (n = 388). Based on modal progression of lengths from July to November, all sizes appeared to be young-of-the-year fish.

Eighteen of fifty- two (35%) Spotfin were recaptured, generally within 10 m of their release point, indicating good short-term survival and high site fidelity. In four consecutive years individuals were collected during early November, at temperatures as low as 12°C. McBride and Able discovered in the laboratory, that Spotfin stopped feeding at about 12°C and did not survive temperatures of about 10°C or less. They concluded that overall, the Spotfin grew and survived for several months in estuarine conditions. They determined that the evidence did not suggest the Spotfin capable of emigrating during autumn, nor surviving winter temperatures. For their conclusion, they proved that Spotfin Butterflyfish become expatriates that will not survive through winter (McBride and Able 2011).

Summary of Recent Research

The research collected shows that Spotfin Butterflyfish stay in the region where they mature, not the region from where their parents are. They do not emigrate. They are not capable of living in thermocline water or winter regions.

Personal Interest

When I first began my research I found the abundance of the Spotfin Butterflyfish (Chaetodon ocellatus) rather odd. I was unaware that they use display confusion as a defense. I discovered that they use the markings on their body to the maximum. They have a black line on their face that goes up and down their eye. This line hides their eye. They have a spot on their dorsal fin, hence the name Spotfin Butterflyfish. The spot is used as a “second eye” to confuse predators on where their head is, because predators tend to go for the head for an automatic kill. When this defense works, the Spotfin is bit on the fin with the spot. This miscalculated bite allows it to escape.

Literature Cited

Please note that the following references may have either been removed or relocated by the webpage owners since the time this student report was created.




Moyle, P., J. Cech. 2000. Fishes: An introduction to ichthyology – fourth edition. Upper Saddle River, NJ: Prentice-Hall.

Helfman, G., B. Collete, D. Facey. 1997. The Diversity of Fishes. Malden, MA: Blackwell.

McBride, Richard S., and Kenneth W. Able. "Ingentaconnect Ecology and Fate of Butterflyfishes, Chaetodon Spp., in the Tempe..." Ingentaconnect Home. Web. 26 May 2011.<>.

External Links

Please note that the following external links may have either been removed or relocated by the webpage owners since the time this student report was created.