Wrought Iron Butterflyfish, Chaetodon daeldama Jordan and Fowler, 1903. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

Founded in 1904, the Waikiki Aquarium is the third oldest public aquarium in the United States. As can well be imagined, during its 102 year history the Aquarium has exhibited a wide variety of fish and invertebrates, many of them for the first time anywhere in the world. The list includes such things as blacktip reef sharks and flashback cuttlefish (Sepia latimanus). Over its long history the Aquarium was the first to display several fish, which at the time were considered rare but are now readily available in the aquarium trade such as the Fiji rabbitfish (Siganus uspi), goldflake angelfish (Apolemichthys xanthopunctatus) and Griffith’s angelfish (Apolemichthys griffisi), the later scientifically described by former Aquarium directors Leighton Taylor and Bruce Carlson in 1981.This tradition has continued into the 21^st century as the Aquarium has been home to several animals that can be seen nowhere else in the world such as Smith’s butterflyfish (Chaetodon smithi), a new species of cardinalfish from Rose Atoll, American Samoa (Ostorhinchus sp. nov.), a Clipperton angelfish (Pomacanthus limbaughi) and Nahackyi’s angelfish (Centropyge nahackyi). The Aquarium also houses a deep Hawaiian reef display that displays the sunrise wrasse (Bodianus sanguineus), the Golden Anthias (Holanthias fuscipinnis), the first tank raised Centropyge sp. species in the world (Centropyge fisheri), and a pair of undescribed butterflyfish collected from 450 ft (137 m) by Dr. Richard Pyle in 1998; Prognathodes n. sp.

* Smith’s Butterflyfish, Chaetodon smithi Randall 1975. Photo by Bruce Carlson.

One of the fortunate advantages the Aquarium has is that it has been managed by the University of Hawaii since 1912. This has resulted in the Aquarium staff having several contacts at the University and the Bernice Bishop Museum; many of these researchers also have extensive connections throughout the south and western Pacific. Among these researchers and contacts are people such as Dr. John Randall, Dr. Richard Pyle, Dr. Bruce Carlson, Dr, Ernest Reese, Dr. Phil Helfrich, Dr. Randall Kosaki, Dr. Pat Colin, Tony Nahacky, John Earle and Brian Greene to name just a few. This has resulted in the donation of several rare fish to the Aquarium such as some of the fish mentioned previously.

In this article I would like to discuss some of the rare species of fish that the Aquarium has displayed over the years and tell you a little about the history and husbandry of each one. Since there are several excellent books available with detailed accounts on the taxonomy and distribution of these species, I will not discuss these aspects and the reader is referred to Allen et al. (1998), Kuiter (2002), Michael (2003, 2004), Randall (2005) and Tanaka (2006).

* Tinker’s Butterflyfish, Chaetodon tinkeri Schultz 1951. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

* = currently on display at the Waikiki Aquarium as of July 2006

Butterflyfish

As butterflyfish go, this is a relatively medium-sized species with a maximum size of 15 cm. What makes this fish unique in the aquarium trade is that it is only found in the water off south and western Japan, in waters somewhat cooler than one would normally think of finding butterflyfish. Therefore, this fish rarely is found at your local retailer or wholesaler. The Waikiki Aquarium has exhibited this fish on several occasions as they were gifts presented to the Aquarium by a Japanese aquarium. They live in small schools in nature and do best when kept either singly or in a small shoal. They are extremely hardy once acclimated, and will eat a wide variety of prepared foods; they are naturally planktivores but will also pick food from the bottom and rocks. This fish does best at tank temperatures of 18 to 24 ^oC, warmer temperatures begin to stress this fish as can be seen by an increase in the respiration rate and a greater susceptibility to parasitic diseases; e.g., Cryptocaryon. I would only recommend this fish for a fish only aquarium than a reef aquarium due to the size of the fish, its activity level (it is an active swimmer) and its need for cooler water.

* Prognathodes sp. (undescribed). Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

A common butterflyfish where it occurs, Smith’s butterflyfish is found in large schools feeding on zooplankton in mid-water, very similar to Hemitaurichthys spp. However, this fish was only discovered in 1967, and not described until 1975, due mostly to its isolated habitat. This species has only been found at the Rapa, Pitcairn and Marotiri Islands, located southwest of Tahiti. In 2002, the Waikiki Aquarium was fortunate to receive a specimen from collector who had traveled there by sailboat from Tahiti and collected 8 individuals. The remaining animals were sold to distributors in Japan, where their fate is unknown. At the time I write this, (October 16^th, 2006) we still have our specimen on display and it has doubled in size. This is a very easy fish to keep which eats a wide variety of food such as frozen mysis, flake food, frozen copepods, pellet food, gelatin mix diet, etc. Given its southerly habitat, this is another species that does best at slightly cooler temperatures and our specimen is kept between 23 and 25 ^oC. It is housed with live corals and has shown not inclination to feed on any of them.

Although not considered a rare fish today, the Waikiki Aquarium was the first aquarium in the world to display this fish, and it was named after Dr. Spencer Tinker, who was the Aquarium’s second director from 1940 to 1973. This is a deepwater species and as such also prefers somewhat cooler water to really be at its best; 22 to 26 ^oC. This is another hardy butterfly that can be purchased as mated pairs, which do quite well in an aquarium. Another active swimming species they should be given a large aquarium to really show their best behaviour. They will eat a wide variety of foods in the aquarium and are considered very hardy once they acclimate to their new home. This fish may eat corals with large polyps and will eat zoanthids and pick at gorgonians as well; they will also eat Aiptasia anemones. If I were to purchase a not so rare but expensive butterflyfish and get my money’s worth, it would be this one … hardy, easy to keep and long lived; we have had ours for 8 years so far.

* Golden Pygmy Angelfish, Centropyge aurantia Randall and Wass 1974. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

In the late 1990s, Dr. Richard Pyle collected three specimens of a new species of butterflyfish at a depth of 125 m off the shore of Diamond Head using a rebreather diving setup. These fish were donated to the Aquarium where they remained on display for several years. We now have two more specimens on display that we have had since 2003. These are hardy fish, but prefer water temperatures to be between 20 and 24 ^oC. They can be somewhat picky in what they eat and seem to prefer eating frozen mysis over any other food offered. We have also observed them picking at the tube feet of sea stars. This fish occasionally appears in the aquarium trade but the majority of specimens are sent to Japan given their high asking price due to the significant risks associated with collecting them. This fish remains undescribed.

Centropyge spp.

In 1998, while on a dive trip to the Solomon Islands, Bruce Carlson and I visited a local fish exporter on our return from diving, and selected a few fish and corals to bring back with us for a new coral exhibit we had constructed. Amongst the fish we selected was a small specimen (3 cm) of C. aurantia. We had never kept one of these fish before and they were only beginning to become more available in the US so we decided to bring this specimen for our new exhibit. It made the 10 hour trip back to Hawaii with little problem and was quickly put through quarantine and added to the new exhibit. This tank is approximately 250 gallons (950 L) and filled with live rock and corals. The fish did not eat extremely well in quarantine but it was decided to put into the display since the live rock and associated organisms should be able to sustain it. Unfortunately, not only did it pick on the live rock it also liked to pick at the live corals as well, mainly Acropora sp. Eventually, the fish began to take flake food as well as frozen mysis.

* Colin’s Pygmy Angelfish, Centropyge colini Smith Vaniz and Randall, 1974. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

The Golden angel is a very shy and retiring fish, and requires a lot of hiding places to feel comfortable. You will rarely see it swimming boldly out in the open but it will be seen dashing from one hiding spot to another and will come out into the water column to feed. For this reason, it is best kept with other small, non-aggressive fish. This specimen has been with us for 8 years now and has grown a little but is still under 5 cm in length.

Colin’s pygmy angelfish is another of the smaller species of Centropyge. This is a deep water species, commonly found below 350 ft (107 m) over its range, but it may be found shallower around the Philippines. The specimen the Aquarium has was donated by Dr. Richard Pyle and was collected at depth in Fiji in 1999. This species is notoriously difficult to get to feed on aquarium foods. This specimen was collected along with several deep water wrasses and Pseudanthias and was housed in quarantine with those same fish. It took several weeks for the C. colini to begin to feed and even then it did so sparingly. The first food we were successful with was frozen mysis and it gradually began to eat live baby brine shrimp. This fish was placed in the same display as the Golden Angel and has been on display since 2000 in that tank. It now eats frozen mysis, flake food, our gelatin based homemade diet and Cyclopeez frozen copepods. Unfortunately, it also enjoys picking at the corals, especially Scolymia. Centropyge colini have been bred successfully in captivity and are occasionally available in the trade (www.rctechnologies.com), however, beware of wild caught specimens, which have flooded the market in response to the higher priced tank-bred specimens; this fish generally do not do well and most end up dying due to their refusal to eat. If you do purchase one make sure it is a tank raised specimen.

Hotumatua’s Pygmy Angelfish, Centropyge hotumatua Randall and Caldwell 1973. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

Rarely collected due to its isolated habitat in the southeastern Pacific, Hotumatua angels do well in captivity. The Aquarium exhibited this fish from 1998 to 2001 until it disappeared from its display tank. It was housed on the same tank as the Colin’s and Golden angels without problem. The fish fed on flake food, gel diet and mysis without difficulty. It occasionally picked at corals but was not seen to be a big problem. This fish is currently in culture and captive bred specimens may appear on the market. Currently this species is available once or twice a year through exporters in Hawaii, the majority of these are sent to Japan where profit margins are much higher than in America or Europe.

The Waikiki Aquarium has a display of fishes commonly found in the Northwestern Hawaiian Islands, a chain of islands, atolls and seamounts stretching 1200 miles (1932 km) northwest of Kauai. Due to their location and the direction of the prevailing currents, the western most of these atolls contain fish also found in Japan and that is where the Aquarium’s specimens of C. interrupta were collected under permit from the US Fish and Wildlife Service on Midway Atoll, back in 1992. This is a relatively easy fish to keep as it will accept a wide variety of foods. It is a larger species (~ 15 cm) than most of the other Centropyge and thus needs a much larger tank to do well. This is another species that has been bred in captivity and offered for sale in the past few years (www.rcthawaii.com) and captive bred specimens are exceptionally hardy. Wild caught specimens from Japan are sensitive to shipping and most do not do well when shipped over long distances. Since this is a more temperate species, water temperatures should be maintained no higher than 77 ^oF (25 ^oC) with 70-75 ^oF (21-24 ^oC) ideal.

* Japanese Pygmy Angelfish, Centropyge interrupta (Tanaka 1918). Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

Located some 1000 miles southwest of Hawaii, Johnston Island is a very remote and isolated coral atoll. The sight of American atmospheric atomic tests in the 1950s and chemical weapons disposal in the 1990’s it should come as no surprise that this island is off-limits to the general public. Administered by the US Fish and Wildlife Service and the US Airforce, only scientific expeditions are now allowed to visit the island and only when the appropriate permits are obtained, which can take up to a year. For this reason, the reefs around the island are pristine and contain a large number of predatory fish such as sharks and jacks. In addition, it is home to Nahackyi’s angel, the only place in the world where this fish is found. Ironically, the specimen that was used to describe the species was collected in Hawaii in deep water, but another specimen has never been found so that one was most likely a waif. In 2000, the Aquarium was granted a permit to collect six of these fish and again this spring, we were again granted a permit to collect and display this fish. That makes the Aquarium the only place in the world that has live specimens of this species. This fish is a finicky eater and does best in a tank filled with live rock where it can graze on sponges, tunicates, algae and other items. It eventually learns to take prepared foods such as frozen mysis, flake good, live baby brine shrimp, Cyclopeez and gel diet. Another large species, they can reach up to 5 inches (7.5 cm) in length.

* Nahacky’s Pygmy Angelfish, Centropyge nahackyi Kosaki 1989. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

Black-spot Pygmy Angelfish, Centropyge nigriocella Woods and Schultz 1953.

Back in the 1970’s, the Aquarium briefly exhibited this fish, but no records remain of its captive care requirements.

Genicanthus spp.

Endemic to the Hawaiian Islands, the Masked angel can be found around the main Hawaiian Islands as well as into the Northwestern Hawaiian Islands chain. However, around the main islands they are only found in deep water, greater than 400 ft (122 m) and so their collection requires the use of specialized dive gear. In the Northwestern Hawaiian Islands, they are found much shallower such that by the time you reach the western most islands (e.g. Midway) they can be found as shallow as 10 ft (3 m). However, these islands are off limits to aquarium fish collectors so the only way to acquire these fish is by using collectors in the main islands that have the specialized equipment to collect this fish (www.twilightaquatics.net/home.html). Due to the depths and risks involved, the price for these fish is understandably very high (>$4000 US retail). In the early 1990’s, the Aquarium has fortunate to receive a permit to collect these fish from Midway Island for display. Eventually they were bred at the Aquarium in 1997 but it took another three years of work before the first juvenile was reared.

* Masked Angelfish, Genicanthus personatus Randall 1975. Male (bottom), Female (top).  Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

Masked angels show sexual dimorphism with the males being much larger and having yellow or orange markings on the face and fins, where the female is normally black. Wild caught males are extremely difficult to get to feed, the chances for success with this species is much better when subadult females are collected. These can still be tough to acclimate to prepared foods but the chances are much better than with the adults. They will eventually learn to accept a wide variety of foods such as frozen mysis, flake food, pellet foods and gel diet. A deep water species, they do best at cooler temperatures such as those mentioned for C. interrupta.

This is again a larger species (21 cm) and as such, requires a tank of at least 350 gallons (1330 L) to do well. Provide plenty of low lying rockwork with a abundant hiding spots and a tall water column for them to swim in. These fish spend most of the time swimming in open water and should provided with the opportunity to do so. This fish is currently in culture and may be more widely available within the next few years. Again, this fish can only be seen on display at the Waikiki Aquarium.

 

Pomacanthus sp.

Clipperton Island lies 1200 km southwest of Mexico in the eastern Pacific and is the only known location where P. limbaughi can be found. In 1998, the Aquarium was fortunate to receive three of these fish from a researcher who had visited the island that year, of which one remains on display. Relatively common in its habitat, it is rarely collected and as far as we know, the Waikiki Aquarium is currently the only place in the world that has this fish on display.

This is an extremely hardy fish and will eat any food offered and is extremely disease resistant. It has done well in a reef exhibit outdoors since 1998 and has tolerated temperatures as high as 84 ^oF (29 ^oC).

Clipperton Angelfish, Pomacanthus limbaughi Baldwin 1963. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

 

Wrasses

Although this fish was known in the trade for several years it has only been scientifically described recently. Commonly called the mystery wrasse, or whitebarred wrasse (due to the vertical white bars seen on juveniles), the correct common name, based on the scientific name, should be the ocellated wrasse. The Waikiki Aquarium first displayed this fish back in the mid-90s and currently has one specimen on display that was obtained from the Marshall Islands in 2001. This is an extremely hardy fish and will take a wide range of foods. They are deep water fish, commonly found between 30 and 90 m and as such do best at somewhat cooler temperatures such as 22 to 26 ^oC. Usually found in caves or under ledges, it is a reclusive fish that will spend more time in open water as it acclimates to the aquarium, but it will never be found far from a safe hiding place.

* Ocellated Wrasse, Pseudocheilinus ocellatus Randall 1999. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

This deepwater wrasse is found only in Hawaii at deeps of 30 to 168 m; the shallower range is more common in the Northwestern Hawaiian Islands. Another fish collected by and donated by Dr. Richard Pyle to the Waikiki Aquarium it is a very hardy and beautiful fish that does best in somewhat cooler water; 20 to 24 ^oC do really do well. Found in small harems consisting of a male and several females over rubble areas. The sunrise wrasse will eat a wide range of foods in the aquarium and is very easy to keep once acclimated. This fish can jump out of the aquarium so a cover is recommended. Again, most specimens collected are sold to the Japanese market do the cost.

Redstripe Fairy Wrasse, Cirrhilabrus roseafascia Randall and Lubbock 1982.

In 2000, the aquarium received a trio of this wrasse from a deepwater collector in Fiji. The fish were collected at 110 m depth using a rebreather diving rig. Unfortunately, the females did not survive for more than a few months but the male was on exhibit for several years until it disappeared one day from our 20 m³ reef tank. A beautiful fish that can eventually acclimate to a brighter tank they will eat a wide variety of foods such as frozen mysis, gel diet, frozen copepods and flake food.

* Sunrise Wrasse, Bodianus sanguineus Jordan and Evermann 1903. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

Bell’s Flasher Wrasse, Paracheilinus bellae Randall 1988.

Bell’s flasher wrasse is not commonly found in the aquarium trade due to its narrow range of the Marshall Islands and Palau, areas that do not have a lot of aquarium collectors that dive deep enough and are able to recognize this exquisite fish. The Aquarium received five of these fish in the late 90s and they proved to be somewhat difficult to keep. They were very shy and did not take well to being placed in a brightly lit tank. Being from somewhat deeper water (30m+) this fish may need to be acclimated to brighter lighting temperatures should be kept between 22 and 26 ^oC. It should also be kept with small, non-aggressive species of fish. As with many of the flasher wrasses, this species is prone to jumping a tank cover is recommended. They fed sporadically on frozen mysis and live Artemia naupili.

Diamond Tail Fairy Wrasse, Cirrhilabrus rhomboidalis Randall 1988.

Another deepwater wrasse from the Marshall Islands, the diamond tail fairy wrasse is commonly found between 20 and 40 m in small harems of one male and several females over rubble areas. The Waikiki Aquarium has exhibited this fish on two occasions and both have proven fairly easy to keep, though they do not like brightly lit tanks or active tank mates. They do best if proved with numerous hiding places placed on the bottom of the tank e.g. small piles of rubble rock. This fish accepts a wide variety of small foods such as frozen copepods, live Artemia naupili. Temperatures should be kept between 22 and 26 ^oC.

* Yellow Anthias, Holanthias fuscipinnis Jenkins 1901. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

 

Others

Another deepwater fish species unique to Hawaii, this large anthias species (24 cm) is only found below 55 m in depth and as such are rarely collected for the aquarium trade. As with most of the deepwater fish, rebreathers or mixed gas diving is required to collect these fish and this results in a high price. Yellow anthias are typically found in small schools or as pairs and require careful decompression to bring up from such depths. Once in captivity and acclimated to the aquarium they are very hardy and will eat a variety of foods. This fish tends to be rather slow moving and feeds in a very leisurely manner so it should not be kept with large, active fish. Given its habitat, a dimmed aquarium with plenty of hiding places kept at 20 to 24 ^oC would provide the best environment for this spectacular fish!

Sunset Basslet, Liopropoma aurora Jordan and Evermann 1903.

This deepwater basslet is also unique to the Hawaiian Islands and is commonly found between 60 and 183 m. This is a very hardy fish and will eat a variety of food including chopped frozen whole shrimp and frozen mysis. Lighting should be kept dim and temperature should be kept between 20 and 24 ^oC; plenty if hiding places should be provided. The Aquarium has exhibited this species in the past in the same tank as Prognathodes and Holanthias with no problems.

* Rose Atoll Cardinalfish, Ostorhinchus sp. nov. Photo by J.C. Delbeek, courtesy Waikiki Aquarium.

In the summer of 2004, the Aquarium was asked to aid researchers in bringing back several specimens of a new species of cardinalfish from Rose Atoll, a small coralline algae dominated reef a days sail northwest of American Samoa. Researchers on a previous trip had found what they thought might be a new species of cardinalfish and during the second trip in July 2004; several specimens were brought to the Aquarium. Some where used by Dr. Jack Randall to determine if it was a new species, and some were used for DNA studies. A pair was kept at the Aquarium and grown to adulthood. These two have since formed a pair and are breeding at least once a month or so. Found in small schools when young, as they grow in size they become more aggressive and begin to separate into pairs. An easy fish to keep, they eat almost anything and are relatively peaceful. Except for the reddish tint on the posterior of the body, they are morphologically identical to O. aureus from the Marshall Islands, but are separated genetically by at least 2 million years, making this a new species.

This concludes our look at the some of the rare fish that have been exhibited at the Waikiki Aquarium over the years. Of course, when dealing with a 102 year old institution, there are naturally several more examples of rare fishes and “firsts,” but those I shall leave for another article.

 

References

1. Allen, G.R., Steene, R. and M. Allen. 1998. A Guide to Angelfishes and Butterflyfishes. Odyssey Publishing/Tropical Reef Research, 250 pp. ISBN: 0-9661720-1-9
2. Kuiter, R. 2002. Fairy and Rainbow Wrasses and their Relatives: A Comprehensive Guide to Selected Labroids. TMC Publishing, Chorleywood, UK, 208pp. ISBN 0-9539097-2-7
3. Michael, S. 2003. The whitebarred wrasse (Pseudocheilinus ocellatus). Advanced Aquarist Online 2(2): February 2003, http://www.advancedaquarist.com/issues/feb2003/Fish.htm
4. ————— 2004. Angelfishes and Butterflyfishes: Reef Fish Series. TFH Publications, Neptune, NJ. 338 pp. ISBN 0-1-890087-69-6
5. Randall, J.E. 1996. Shore Fishes of Hawaii. Natural World Press. Vida, OR. 216 pp. ISBN 0-939560-22-4
6. —————– 2005. Reef and Shore Fishes of the South Pacific: New Caledonia to Tahiti and the Pitcairn Islands. University of Hawaii Press, Honolulu, 707 pp. ISBN 0-8248-2698-1
7. Tanaka, H. 2006. Fairy wrasses: Newcomers to the hobby. Reefkeeping Online 5(5) June 2006. http://www.reefkeeping.com/issues/2006-06/ft/index.php