Sunset Butterflyfish

The Sunset Butterflyfish isa more colorful butterflyfish but is also more difficult to keep in captivity!

The Sunset Butterflyfish Chaetodon pelewensis is a classic beauty and a visual treat. Though moderately small in size, only reaching about 5 inches (12.5 cm) in length, it has a dramatic color patterning that is likened to the setting sun. The body has brilliant yellow to orange hues adorned with elegant diagonal bands that gradually break into spotted lines. The dorsal fin is trimmed in bright yellow, the anal fin in white, and there’s a bright splash of orange on the tail. These decorative markings have led to other common names including Dot and Dash Butterflyfish, Dot-and-Dash Coralfish, and Dot-Dash Butterflyfish along with Pelewensis Butterflyfish derived from the scientific name.

Another species also frequently called the Dot and Dash Butterflyfish, or Dot Dash Butterflyfish, is the Spot-banded ButterflyfishChaetodon punctatofasciatus. The main visual difference between these two species is the orientation of their spots and bands. On the Sunset Butterflyfish they run diagonally throughout and one the Spot-banded Butterflyfish they are aligned vertically on the upper portion of the body and horizontally below.

If you are getting a ‘Dot-and-Dash’ Butterflyfish you will definitely want to know which species you are obtaining. Though they look very similar, they differ in the degree of difficulty in keeping them. The Spot-banded Butterflyfish is one of the easier fish to maintain while this butterflyfish is quite a bit more challenging. In nature it feeds heavily on soft and hard coral polyps as well as some invertebrates and vegetable matter. Generally it will readily accept substitute foods, but its diet must be closely watched and include live food. It is also rather sensitive to water changes including pH, salinity and temperature, and canbe sensitive to drug treatments.

These two butterflyfishare known tocross breed in the the Western Pacific. The hybrids are collected and shipped on occasion, and they too are labeled as the ‘Dot-and-Dash’ Butterflyfish. Hybrids have intermediate but variable color patterns of the parental species. Usually the dots form a wavy diagonal, but a great curiosity is when an occasional hybrid will have the pattern of one parent on one side and the pattern of the other parent on the other side.

This fish is very attractive and is reasonably priced, but because it is a more sensitive butterflyfish it is suggested for a more experienced aquarist. It needs a good sized aquarium that is well established. A 55 gallon tank is the suggested minimum size. Decorate the tank with rocks creating many caves for hiding places and lots of rocky rubble. Also make sure there is plenty of swimming space. Though not a very quick swimmer, it swims freely and usually spends a good deal of its time in the open water. It will go up to the surface to take foods when it is well accustomed to its environment.

As the Sunset Butterflyfish is fond of the live polyps of both hard and soft corals, it is not recommended for reef-type settings other than those containing only stinging anemones and mushroom anemones. It is a non-aggressive fish and can do well in a fish only community tank. It can be kept with a variety of other butterflyfish, including members of its own species if introduced at the same time. It can also be kept with other species of a similar temperament, as well as some rather aggressive species such as the larger and rather territorial angelfish like Pomacanthus and Holacanthus.

For more Information on keeping saltwater fish see:
Marine Aquarium Basics: Guide to a Healthy Saltwater Aquarium

Habitat: Distribution / Background

The Sunset Butterflyfish Chaetodon pelewensis was described by Kner in 1868, and was first collected in Palau. Its scientific name pelewensis was derived from the locality. They are found in the South Pacific Oceans; Palau, Great Barrier Reef, New Caledonia, Lord Howe Island, Papua New Guinea, Solomon Islands, Fiji, Samoa, Tonga, Cooks, Societies, Marquesas, Tuamotu Archipelago. This species is on the IUCN Red List as Least Concern (LC) as they have a wide distribution and there are no major threats currently identified. Other common names they are known by include Dot and Dash Butterflyfish, Pelewensis Butterflyfish, Dot-and-Dash Coralfish, and Dot-Dash Butterflyfish.

This fish is a member of a close-knit group of butterflyfish in the subgenus Exornator. This group is comprised of four species that are very similar in appearance, though they do differ in being adaptable to captivity. The other three members are the Peppered ButterflyfishChaetodon guttatissimus, Pebbled ButterflyfishChaetodon multicinctus, and Spot-banded ButterflyfishChaetodon punctatofasciatus. These four are suspected to be able to produce fertile hybrids. The Spot-banded Butterflyfish C. punctatofasciatus has hybridized with the Peppered Butterflyfish C. guttatissimus and the Sunset Butterflyfish C. pelewensis.

The Sunset Butterflyfish are found at depths between 1 – 98 feet (3 – 30 m). Their natural habitat is clear coral rich areas and rocky reefs of lagoons and the slopes and faces of seaward reefs. In some areas the adults tend to occur in the deeper waters below 66 feet (20 m) level while the juveniles favor the shallow waters at depths of less than 33 feet (10 m). Adults are seen mostly in pairs, though the juveniles and an occasional adult will be seen alone. They feed on a variety of foods with the bulk of their diet being the polyps of hard and soft corals which they supplement with algae, polychaete worm tentacles, and peanut worms.

• Scientific Name: Chaetodon pelewensis
• Social Grouping: Pairs – They are usually seen in pairs, though are sometimes seen alone.
• IUCN Red List: LC – Least Concern

Description

The Sunset Butterflyfish has a disc shaped body that is laterally compressed and it has a protruding snout tipped with a small mouth. The dorsal fin is continuous and it has a rounded tail fin. This species grows to a length of just over 5 inches (12.5 cm), but most available specimens are less than 3 1/2 inches (9 cm). The lifespan for most of the Chaetodon species is between 5 – 7 years, but sometimes longer with proper care.

The adult C. pelewensis has a yellowish brown body that is more of a yellow tan on the lower half and yellow on top. There are several deep brown bands running vertically and spots all over. The spotting on the upper half forms broken vertical stripes while those on the lower half become horizontal stripes. There is an orange area on the caudal peduncle, an orange band edged by black through the eye, and a black spot on the nape. The fins are a yellowish brown except for the pelvic fins which are white. The dorsal and anal fin both have a yellow margin with a black sub marginal line. The caudal fin is yellow basally with a black line centrally and the rest is transparent. Juveniles are very similar but a more creamy white, becoming more yellow as they mature.

This species is very similar in body shape and colors to its close relative the Spot-banded Butterflyfish C. punctatofasciatus, and they mix in some ranges. Hybrid crosses are observed and shipped from these areas on occasion. The hybrids have intermediate but variable color patterns of the parental species. Some of the patterns are rather complicated with irregular bands and spots, however almost all cases can be readily distinguished from other species of Chaetodon.

• Size of fish – inches: 4.9 inches (12.50 cm)
• Lifespan: 5 years – The average lifespan Chaetodon species is between 5 – 7 years, and possibly longer with proper care.

Fish Keeping Difficulty

This fish is moderately hardy and is suggested for an intermediate aquarist. In the aquarium they will readily accept substitute foods, however its diet must be monitored carefully. It must be offered a wide variety of proteins along with algae and live foods. This fish is also rather sensitive to changes in its water conditions including pH, salinity and temperature, and it can also be sensitive to drug treatments. Because it will harm the polyps of hard and soft corals, it is not recommended for reef-type aquariums.

• Aquarium Hardiness: Moderately hardy
• Aquarist Experience Level: Intermediate

Foods and Feeding

The Sunset Butterflyfish are omnivores. In the wild they eat lots of hard and soft coral polyps along with algae, polychaete worm tentacles and peanut worms. In the aquarium it will readily accept substitute foods. Provide a variety of finely chopped meaty foods such as fresh or frozen seafood, live brineshrimp, and blackworms, dried flakes, shrimps, tablets, and Japanese Nori (Asakusa-nori).

They have a very small mouth so all foods must be very fine. Also provide algae and prepared frozen formulas including those containing algae. Once it is successfully acclimated it can become hardy and live for some period. Feed it at least twice a day, and if it is a tiny juvenile, feeding should be tried three to four times everyday.

• Diet Type: Omnivore
• Flake Food: Yes
• Tablet / Pellet: Yes
• Live foods (fishes, shrimps, worms): Some of Diet
• Vegetable Food: Some of Diet
• Meaty Food: Some of Diet
• Feeding Frequency: Several feedings per day – Offer various foods quite frequently at first. Once acclimated adults need at least 2 feedings a day and juveniles need 3 to 4.

Aquarium Care

Once adapted no special care or technique is needed to maintain this fish in the aquarium. Frequent water changes are not necessary, rather normal water changes at 10% biweekly or 20% monthly are fine. Sudden massive water changes can cause trouble and this fish is rather sensitive to changes in its water parameters.

• Water Changes: Bi-weekly – Change 10% biweekly or 20% monthly, avoid sudden massive water changes.

Aquarium Setup

These fish need plenty of space to accommodate their size and to swim. As they can reach almost 5 inches in length, a 55 gallon tank is the minimum size for a single fish and a bigger tank will be needed if you want to keep a large community. The tank should be established and a good algae growth will help in keeping this fish. This fish is not a very quick swimmer and will spend a good deal of its time in the open areas. Even so, the tank should be well decorated with a rocky environment creating numerous caves and lots of rubble. This fish will nip at the polyps of hard and soft coral species, so it is not recommended for coral-rich reefs.

• Minimum Tank Size: 55 gal (208 L)
• Suitable for Nano Tank: No
• Live Rock Requirement: Typical Plus Hiding Places
• Substrate Type: Mix – Sand + Coral
• Lighting Needs: Moderate – normal lighting – It is best kept under the normal lighting conditions, but can also be kept under very bright light as long as some dimly lit spaces are provided.
• Temperature: 72.0 to 81.0° F (22.2 to 27.2&deg C) – Avoid temperatures higher than 84° F (29° C) or below 68° F (20° C).
• Specific gravity: 1.020-1.025 SG
• Range ph: 8.1-8.4
• Brackish: No
• Water Movement: Weak – Water movement is not a significant factor. It can tolerate a rather strong flow but slow-moving water will be more favorable.
• Water Region: All – It swims freely and usually spends time in the open water.

Social Behaviors

The Sunset Butterflyfish is a non-reef safe fish. Though it does well in a coral-rich tank, it will nip the polyps of hard and soft coral species. It it best kept in a fish only community tank that is well decorated with rocks that create caves for hiding places and lots of rocky rubble.

This fish is initially shy and is generally not an aggressive species. It is best to select other tank mates that are not overly territorial or aggressive. It will get along well with other butterflyfish, as well as other members of its own kind. For success inkeeping more than one they should beintroduce into the aquarium at the same time.

Smaller non-aggressive fishes like cardinal fish, gobies, tilefish, fairy basslets, fairy and flasher wrasses are good candidates as tank mates. It can also be kept with the larger and rather territorial angelfishes like Pomacanthus and Holacanthus.Centropyge, along with other angelfish members of Apolemichthys, Genicanthus, Chaetodontoplus and Pygoplites could also be good tank mates. Small but very territorial fishes like dottybacks should be avoided. Such fish as Basses or scorpionfish, even if they are small enough, should also be avoided. Larger frogfishes can swallow everything, so also should be avoided.

• Venomous: No
• Temperament: Peaceful
• Compatible with:
  • Same species – conspecifics: Yes – Introduce them into the aquarium at the same time.
  • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Safe
  • Semi-Aggressive (anthias, clownfish, dwarf angels): Monitor
  • Threat
  • Large Semi-Aggressive (tangs, large angels, large wrasses): Monitor
  • Large Aggressive, Predatory (lionfish, groupers, soapfish): Threat
  • Monitor
  • Anemones: Safe
  • Mushroom Anemones – Corallimorphs: Safe
  • LPS corals: Threat
  • SPS corals: Threat
  • Gorgonians, Sea Fans: Threat
  • Leather Corals: Threat
  • Soft Corals (xenias, tree corals): Threat
  • Star Polyps, Organ Pipe Coral: Threat
  • Zoanthids – Button Polyps, Sea Mats: Monitor
  • Sponges, Tunicates: Monitor
  • Shrimps, Crabs, Snails: Monitor
  • Starfish: Monitor
  • Feather Dusters, Bristle Worms, Flatworms: Threat
  • Clams, Scallops, Oysters: Threat
  • Copepods, Amphipods, Mini Brittle Stars: Threat

Sex: Sexual differences

No sexual difference is noted for this species. Butterflyfish species studied up to this time indicate that these fish are gonochoristic, meaning that each fish is either a male or a female and they do not change sex.

Breeding / Reproduction

This species has not been cultivated in captivity. In the wild butterflyfish are pelagic spawners that release many tiny eggs into the planktonic water column where they float with the currents until they hatch. Once hatched the fry are in a post-larval where their body, extending from the head, is covered with large bony plates.

Marine butterflyfish have not reportedly been spawned successfully in captivity. There are however, reports of some success in rearing wild collected larvae of some of the corallivorous butterflyfish. It is hoped these captive reared fish will be adapted to accept aquarium foods, and thus broaden the species selections that can be sustained in captivity. For more information see, Marine Fish Breeding: Butterflyfish.

• Ease of Breeding: Unknown

Fish Diseases

Many of the Chaetodon members are often very colorful and attractive to aquarists. Unfortunately some of them are rather difficult to keep for a long period. Some are exclusively coral eaters, and sometimes they suffer from “ich” (white spot disease) and other infectious diseases. Problems with disease are reduced in a well maintained aquarium. Any additions to a tank can introduce disease, so it’s advisable to properly clean or quarantine anything that you want add to an established tank prior to introduction.

Diseases that marine Butterflyfish are susceptible to include Marine Ich(white spot disease), Marine Velvet, Uronema marinum, and Lymphocystis. Some can be treated successfully with medical care or copper drugs, but some species hate sudden changes of water including PH, temperature, or any drug treatment. In the wild a cleaner wrasse (Labroides sp.) will help them by taking parasites from their bodies, however these wrasses are extremely difficult to sustain in captivity. Alternative fish such as Neon Gobies (Gobiosoma spp.) can help them by providing this cleaning service in the home aquarium.

The Sunset Butterflyfish, though moderately hardy and disease resistance, is sensitive to some drug treatments. Be sure to observe this fish closely when medicating it, so you can remove it if it shows signs of stress. For information about saltwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.

Availability

The Sunset Butterflyfish is often available online and in pet stores and is relatively inexpensive. Most of those that are available are smaller than 3 1/2 inches (9 cm). However juveniles less than 1 1/2 inches (4 cm ) are rarely obtainable.

References

• Animal-World References: Marine and Reef
• Chaetodon pelewensis (Kner, 1868) Sunset butterflyfish, Fishbase.org
• Chaetodon pelewensis, The IUCN Red List of Threatened Species
• Helmut Debelius, Rudie H. Kuiter, World Atlas of Marine Fishes, Hollywood Import & Export. Inc., 2006
• Scott W. Michael, Angelfishes & Butterflyfishes: Reef Fishes Series , Microcosm Ltd, 2004
• Robert M. Fenner, The Conscientious Marine Aquarist: A Commonsense Handbook for Successful Saltwater Hobbyists , TFH Publications, 2001
• Mark Allen, Roger Steene and Gerald R. Allen, A Guide to Angelfishes and Butterflyfishes , Odyssey Publishing, 1998
• Dr. Warren E. Burgess, Dr. Herbert R. Axelrod, Raymond E. Hunziker III, Dr. Burgess’s Atlas of Marine Aquarium Fishes, T.F.H Publications inc., 1990
• Roger Steene, Gerald R. Allen, Hans A. Baensch, Butterfly and Angelfishes of the World, Volume 1, John Wiley & Sons, 1980
• Warren E. Burgess, Butterflyfishes of the World, TFH Publications,1978
• Kuiter, R.,, TMC-Publishing, UK, 2002
• Kner, R., Ueber neue Fische aus dem Museum der Herren Johann Caser Godeffroy und Sohn in Humburg, Sitzber. Akad. Wiss. Wien., 58; 293-395, 9plts., 1868.