Nahacky’s Pygmy Angelfish (Centropyge nahackyi) is a rare deep water species of pygmy angelfish that is found only at the Johnson Atoll, west of the Hawaiian Islands at depths between 85 to 250 feet.
Although a single stray Nahacky’s Pygmy Angelfish that was collected in 1989 in the seaward slopes of the Neritic zone in the Hawaiian Islands has led tropical fish keeping enthusiasts to believe that their range is much more extensive than reported; the difficulties of sampling deep reef environments makes their precise distribution unknown.
Nahacky’s Pygmy Angelfish inhabit the coastal ocean which is also known as the Neritic zone, coastal waters, or sublittoral zone which is slightly above the drop off of the continental shelf and extends to depths to 330 feet. Because of the abundant sunlight of sunlight and nutrients in this zone, it is where the majority of corals and marine fish species in our oceans reside.
The Abei Angelfish is the deepest living species of dwarf angelfish found in this zone at a depth of 600 feet, but Nahacky’s Pygmy Angelfish and several other species also enjoy deeper water in the 80 to 250 feet range.
Nahacky’s Pygmy Angelfish prefer living in small groups or harems along the seaward slopes of the continental shelf close to collections of rubble where they hide among the crevices and overhangs.
Nahacky’s Pygmy Angelfish (Centropyge nahackyi) is a beautiful deep water species that is colored a vibrant dark blue on the upper half and mostly yellow on the lower half of it’s body. It has several squiggly black and bright blue lines over the eye, a bright yellow tail, and a black anal fin edged with bright blue. Except for possibly size, there are no obvious differences between sexes.
Like all Centropyge species, Centropyge nahackyi start their adult life as females. Over time, the larger and more dominant individual in a small group or harem will change sex; sometimes within a few days, up to a couple of weeks to become a male.
Understanding that size is the main difference between sexes, many tropical fish keeping enthusiasts place a small and larger specimen together to develop breeding pairs. Usually in just a couple of months, one of the two fish will change sex to accommodate the other.
Should the need arise, a reversal of this sex change is also possible, but it requires weeks to months for the change to occur.
Because Nahacky’s Pygmy Angelfish is so rarely seen in the aquarium trade, not much is known about its diet or aquarium care, however, a couple of Japanese specimens are housed like other species in this genus.
Nahacky’s Pygmy Angelfish do best in a well established aquarium of at least 55 gallon capacity with a large quantity of live rock arranhed into caves, crevices, and overhangs for them to hide among when they feel threatened. A reef setting is optimal however, like other pygmy angelfish, Centropyge nahackyi has a tendency to nip at clam mantles, sea anemones, large polyp stony corals, and some soft corals such as zoanthids; especially when underfed.
Although Centropyge nahackyi are believed to be broadcast spawners; nothing is known about the breeding habits of this species.
Nahacky’s Pygmy Angelfish are omnivores that require a sufficient amount of live rock in their aquarium for them to graze on, and live or frozen small meaty items such as live sponges, fortified brine shrimp, mysis, and flake foods offered several times a day.
Because Nahacky’s Pygmy Angelfish (Centropyge nahackyi) is a deepwater species found only at the Johnston Atoll at depths where sharks are abundant; only two or three specimens have been imported at ridiculously high prices to aquariums in Japan. Listed as NT (near threatened) on the Red List, it is unlikely that any specimens will be available to tropical fish keeping enthusiasts in the United States.
Minimum Tank Size: 55 gallons
Aquarium Type: Deepwater Reef
Care Level: Easy
Temperament: Semi-aggressive
Aquarium Hardiness: Hardy
Water Conditions: 70 – 79°F, dKH 8 to 12 , pH 8.0 – 8.5, sg 1.020-1.027
Max. Size: 3.6″
Color Form: Black, Blue, Yellow
Diet: Omnivore
Compatibility: Reef w/Caution
Origin: Johnston Atoll
Family: Pomacanthidae
Lifespan: 10 years
Aquarist Experience Level: Expert