BNSullivan.jpg "A Multiband Butterflyfish (Chaetodon multicinctus) feeding on Porites lobata coral in Hawaii")
These fishies are rather small -- about 10 cm (4 in) in length -- and their natural diet consists solely of coral polyps, especially those corals in the Poritidae family. The fish in the photo on this page is about to feed on a head of Porites lobata, a common stony coral on Hawaiian reefs that seems to be a favorite food of C. multicinctus. They feed by pecking on the coral head, extracting individual polyps.
C. multicinctus is a plentiful species on most coral reefs in Hawaii, and they are seen frequently by divers. They don't shoal. or school; instead they live as monogamous pairs that remain together over long periods of time, perhaps for life. In case you are wondering, no one knows for sure how long 'life' is, but one researcher we know who studied this species told us their natural lifespan may be in the neighborhood of 15 years (providing they don't get eaten!).
These guys are quite territorial. Observational studies of the species in its natural environment have shown that pairs establish territories of 50-100 square meters. Once established in their territory, a pair will remain there together and defend it from potential competitors, actively aggressing against intruders of the same species. Some pairs have been observed maintaining the same territory for periods greater than four years. It's possible that they stay in the same territory for a lifetime, but again, no one has systematically observed a given pair longer than four or five years.
Like virtually all species in the Butterflyfish (Chaetodontidae) family, C. multicinctus is diurnal. That is, they are active throughout the daylight hours, and at night they hide in crevices in the reef to take their rest.
By the way, some fish identification books and cards identify C. muticinctus by its alternative common name, Pebbled Butterflyfish. Presumably that name refers to the vertical rows of speckles on the fish. We also have seen it referred to as the Brown-barred Butterflyfish. We prefer the common name Multiband Butterflyfish, since it is a literal translation of the fish's species name multicinctus. (Or, as we often advise, avoid the confusion of variable common names. Just learn the scientific name and be done with it!)
Note: For readers who may be interested in territorial behaviors and intra-specific communication by C. multicinctus, we recommend you have a look at: Tricas, TC, et al. (2006). Acoustic communication in territorial butterflyfish: test of the sound production hypothesis. Journal of Experimental Biology, 209 (24), 4994-5004.
Fidelious fish! Will wonders never cease?
ReplyDeleteMonogamy is not altogether common in the animal world, especially so for fish...making this guy all the more surprising.
ReplyDeleteRe 'monogamous' fishes: The purpose of the pairing is less about reproduction and more about making a living. These fishes (and some others that live as pairs) do not necessarily mate monogamously to produce offspring, and they do not care for their young. Instead, the pairing seems to be a strategy for maintaining and defending a food patch for themselves.
ReplyDeleteIn general, critters that stay put in a relatively small range are the ones that are the most likely to be territorial and the most likely to live as stable pairs. Critters that are more or less constantly mobile and have a larger range seem more likely to live as singles or in aggregations.
Bobbie