The Sunburst Butterflyfish (Chaetodon kleinii)

Author: Robert Fenner

The sunburst butterflyfish (also known as Klein’s butterfly) is a hardy addition for most reef tanks. Learn more about this species’ history, diet, and needs.

Though most butterflyfishes are rather delicate, some barely skating along the edge of aquarium suitability, there are a handful of tougher species that tend to do well in aquariums. Among these is the sunburst butterflyfish (Chaetodon kleinii). This fish is a not-to-picky feeder, a good shipper, active and intelligent, and a great beauty.

Considering the sunburst butterflyfish’s wide range, healthy population makeup, and ease of collection, it seems strange to me that this species is not more frequently encountered in the ornamental marine trade. Let’s review a little about its native habitat and habits, go over some things to look for when selecting a specimen for your own aquarium, and review the proper setup for this magnificent and relatively hardy reef fish.

Natural History

Also known as Klein’s butterfly, C. kleinii occurs throughout the tropical Indo-Pacific, East Africa to the Galapagos, and the Red Sea. It can be found in good numbers in Hawaii, southern Japan to Samoa, Noumea, and New South Wales, Australia. Very large specimens can approach 6 inches (15 cm) in total length, though most top out at a modest 4 inches (10 cm).

If you have had the privilege of participating in dive-adventure travels in one of these areas, as I have been fortunate enough to have enjoyed many times, you’d find that this butterflyfish is fairly typical of the bottom-hanging small invertebrate feeders in the family Chaetodontidae. Like others of that family, the sunburst butterflyfish’s feeding habits mostly involve cruising about coral reefs by day, seeking out little mollusks, crustaceans, and worms to snack on.

Other butterflyfishes largely feed on live coral polyps, and a dozen or so are midwater planktivores by and large, but the sunburst will usually leave most corals and their close relatives alone—though they have been known to occasionally nip hard and soft corals, such as leathers. These incidents are rare, however, and can be prevented for the most part if the fish are supplied with palatable foods at short intervals. I’ve listed some food and feeding recommendations below that you may find helpful. The species has been touted as a pest Aiptasia anemone controller, as well. 

As a side note on their feeding habits in the wild, I have observed their behavior of “mobbing” other nesting fishes to consume their eggs. While diving on N.E. Sulawesi in Indonesia’s Lembeh Strait, I watched a group of C. kleinii that had rushed a nest-sitting three-spot damsel (Dascyllus trimaculatus) en masse, confusing the damsel long enough for the swarm of butterflies to consume the contents of its nest.

Aquarium Requirements

If I had to summarize the needs of this species—or, indeed, of all butterflies that are suited for aquariums—in just two words, those words would be “tank space.” These fish require plenty of room for such activities as swimming about, looking for food items, and avoiding tankmates (as well as nosy humans) to feel comfortable. I strongly suggest a minimum of 100 gallons (380 liters) for keeping one specimen, 150 gallons (570 liters) for two, and 200 gallons (760 liters) for three. 

As far as what sort of water quality is best and what kind of tank setup is required for C. kleinii, conditions worthy of a coral reef are an absolute must. Butterflyfishes are decidedly not candidates for fish-only (FO) or even fish-only-with-live-rock (FOWLR) aquaria. Good aeration, a full 7 to 8 ppm of dissolved oxygen, reasonable redox/ORP, and alkalinity are the chief measures I would use to evaluate what is going on in your system as far as water quality goes.

Selection and Stocking

In the family Chaetodontidae, sunburst butterflies are among the easier, if not the easiest, species to find and purchase. This fish, especially when collected and shipped out of Hawaii (to aquarists in the continental United States), is almost always received in good shape. It acclimates well and is typically up and feeding within a day of arrival.

There are a few issues to check for, though, as with all wild-collected specimens. First, check for torn fins, bruises, and bloody marks on the fins and body. If these are evident, leave the specimen there.

Second, look for signs of a damaged mouth. This can indicate very real trouble with the fish, and it can be hard to discern. This fish, like most marine fishes, should not be shipped in bags that are upright. In the packing boxes, where there is no light, the fish should be lying on their sides (as they do in the wild at night), greatly reducing the likelihood of the animal dashing itself into the bag and damaging its mouth.

And lastly, make sure they’re feeding, and doing so on the types of foods you intend to feed them at home. Non-feeding animals are a nonstarter for me. If you must have a fish but haven’t seen it eat in the dealer’s tank, put a holding deposit down and collect the specimen a few days or even a week later, but only after you’ve personally seen it eating. 

Most butterflyfishes are argumentative with their own kind, except in mated pairs or (very) occasional groupings, but not C. kleinii. This Chaetodongets along fabulously with others of its species, and, in fact, it actually gets along pretty well with any other animals that also get along with it. There are few aquarium displays more beautiful than biotope-type setups showing different organisms interacting with one another.

For folks living in the United States, check out the source of the animals you’re considering. Those hailing from Hawaii and Fiji are superior and take much less of a beating being shipped to the mainland than those from more far-flung locales. For other folks, including those in Europe, the specimens from the Red Sea and East Africa are better.

Foods and Feeding

As previously stated, some butterflies eat little, if anything, in captivity except for live coral polyps. This is not the case for the sunburst butterflyfish, which accepts all food formats readily, be they dried, live, or frozen.

My favorite approach is to maintain as large as possible and practical a refugium, tied-in with the main/display system, and set the lighting for a reverse-daylight photoperiod that runs inverse to the principal aquarium’s light regimen. Most of the small live organisms will come out and reproduce during the night, and this light arrangement provides a good deal of fare for the display-tank livestock. 

In addition, I would offer a nutritious, highly palatable pelletized food of good quality at least twice daily, as well as a mix of small frozen seafood organisms, defrosted for the fish, at least once per day. 

A Hardy Gem for the Reef Tank

Although usually encountered in the trade under the name “Klein’s butterfly,” I think the name more commonly used by the scientist set for C. kleinii, the “sunburst butterfly,” is much more apt for this gorgeous, shining, reef- and tankmate-friendly species. 

Aside from the above names, this species is also often labeled the corallicola, yellow, orange, or blacklip butterflyfish. Whatever name you may find it under, it is an exemplary, hardy, beautiful, and fairly low-cost member of the butterflyfish family that is perfect for larger reef-aquarium setups.

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