Arc-eye Hawkfish

The arc-eye hawkfish is easily recognized by the U-shaped ring of orange, red and blue lines curving behind its eye. Body color varies from individual to individual: it may be pinkish, red-brown or olive, and many individuals have a pale horizontal stripe on the rear half of the body. The eye ring, however, is present in every color form.

Hawkfish have no swim bladder; so they perch on rocks and corals, propped on their thick pectoral fins, wait for prey and pounce on it in an instant. It is a very hardy, easy-to-feed fish with plenty of personality. In the wild it can reach up to 20 cm, but in the aquarium it mostly stays at 12–14 cm.

It lives in lagoons and on outer reefs of the Indo-Pacific from East Africa to Hawaii, mostly at depths of 1–33 meters. It perches on top of small branching corals such as Stylophora, Pocillopora and Acropora and hunts passing shrimp, crabs and small fish. It lives alone.

• Volume: at least 200 liters.
• Water: salinity 1.023–1.026 specific gravity, pH 8.1–8.4, temperature 24–27°C.
• Layout: rock tops and sturdy corals to perch on; high points from which it can watch the whole aquarium.
• Reef compatibility: reef safe with caution. It does not touch corals, but it hunts small ornamental shrimp, crabs and small fish that fit in its mouth. Even large cleaner shrimp are sometimes targeted.
• Corals: soft corals or delicate LPS polyps it constantly perches on may become irritated over time.

Carnivorous. Offer frozen mysis, krill, brine shrimp, finely chopped seafood and granules. It is greedy and gets used to food right away. 1–2 times a day is enough; avoid overfeeding.

It moves by hopping from rock to rock and watches every corner of the aquarium. It is territorial toward fish smaller than itself and toward its own kind or other hawkfish. It lives compatibly with fish larger than itself that can defend themselves.

Good companions: tangs, dwarf angelfish, large damsels, foxface, large wrasses, clownfish (of similar size).

Avoid: ornamental shrimp, small fish such as neon gobies, firefish and dartfish, other hawkfish, larger predators such as lionfish.

Keep it singly. Although it is known to form pairs in the wild, two individuals usually fight in the aquarium; a mated pair can only be tried in a very large aquarium. It is not kept with other hawkfish species.

At dusk the pair rises a short distance into the water column and releases eggs and sperm; the eggs drift with the current. Raising the larvae in the aquarium is not a known practice.

• A very hardy species; quarantine a new fish for 3–4 weeks.
• Marine ich and velvet: watch for them in quarantine.
• Overfed individuals develop fat buildup.

There is no reliable external difference. Hawkfish can start out as females and change into males; the dominant, larger individual is usually the male.