Care
The Marquesas Butterflyfish is known from rocky and sandy deepwater habitats at Christmas Island in the Eastern Indian Ocean and at Line and Marquesas Islands in the Eastern Central Pacific. This small-sized butterflyfish is one of a complex of several similar looking fish and is only sporadically seen in the aquarium trade. This species is regarded as moderately difficult, and is therefore recommended for advanced aquarists only. A good-sized, mature system is requisite, along with ample live rock for the fish to browse upon/hide amongst and a large open swimming space along the front of the aquarium. Water temperature should be lower than average on account of these fish hailing from deeper, slightly cooler waters (typically 20-80m/66-263ft). Medium sized specimens tend to acclimatise better to aquarium life, adapting much more quickly to various prepared foods, so try and choose a healthy, alert specimen around 7cm (2.8") in length. Smaller sized fish may be reluctant to feed, and larger specimens can sometimes be rather finicky, requiring faultless water conditions. An aquarium that has some areas of lush filamentous algae growth will also aid your new fish in settling into its new surroundings; however, as with other butterflyfish species, these fish demand excellent water quality - thoroughly filtered and well oxygenated, with areas of brisk current. Some aquarists have successfully kept the Marquesas Butterflyfish alongside some of the more noxious soft corals, but this is something of a risk, and they should be observed carefully. Stony corals and many other sessile invertebrates will be constantly nipped at, so unfortunately must be avoided. Keep only one Marquesas Butterflyfish per tank (unless a mated pair is acquired) and not with any other butterflyfish as they will squabble over territories. Whilst they can be a little shy when first introduced, providing them with ample retreats amongst the live rock will ensure they quickly gain confidence and venture out into the open. Once settled, these intelligent, peaceful fish actually become very assertive feeders, competing with most other fish species, and they will also be most curious of any activity in and around their aquarium. Tankmates should be of similar size and temperament. As mentioned above,
C. declivis forms part of a complex of similar-looking, deepwater fish known as the Tinker's Complex, which also includes
C. burgessi,
C. flavocoronatus,
C. mitratus, and
C. tinkeri. Where these species overlap in the wild, it is not uncommon for them to hybridise. The scientific name '
declivis' is from the latin, meaning 'sloping' and is in reference to the abrupt diagonal demarcation in the colour pattern. May also be seen on sale as Marquesan Butterflyfish or Declivis Butterflyfish.
Feeding
Feed small amounts several times per day, and be sure to offer a good variety of different foods. Frozen fare such as Mysis shrimp, vitamin-enriched brineshrimp, finely chopped clam/mussel/cockle/crab/shrimp/squid etc. can be proffered, but - most importantly "“ do ensure that the larger foodstuffs are chopped into small enough pieces on account of butterflyfish having tiny mouths.
Breeding
This species has not been bred in captivity. In the wild, these fish form distinct pairs and scatter their eggs in open water.
