Xanthichthys caeruleolineatus is a robust, laterally compressed triggerfish that reaches roughly 14 inches as an adult. The body is olive-brown to yellowish tan above and pale gray below, with the two fields separated by a narrow blue line that is sometimes bordered in orange. Blue cheek grooves, blue markings across the upper-body scales, an orange-and-blue stripe on the face, and red borders along the concave tail make identification straightforward. The species ranges widely through the Indo-Pacific, including oceanic islands of the eastern Pacific, where it lives on rocky or coral-rich seaward reefs at depths of about 15 to 200 meters.

Adult housing should be generous: plan on an aquarium of at least 250 gallons so this large, powerful swimmer has open water to patrol. Build reef rockwork with caves and crevices deep enough for the fish to wedge into, since wild individuals retreat into shelter to hide and to rest at night. Because its natural habitat consists of current-swept seaward reefs where it hovers just above the bottom, an open sand or rock-bottom zone beneath the rock structure suits its swimming pattern well. Scattering a few small shells on the substrate gives the fish objects to manipulate and bite, which helps wear the continually growing teeth.

In the wild this triggerfish is a zooplankton feeder, taking drifting prey above the reef, with pelagic fish larvae also reported in its diet. In captivity it accepts a broad range of meaty marine items, including mysis shrimp, vitamin-fortified brine shrimp, chopped shrimp, fish flesh, squid, clam meat, and frozen carnivore preparations. Variety matters more than volume at any single feeding, so rotate items rather than relying on one staple.

Two or three small feedings per day suit its metabolism and keep an actively swimming adult in good condition. Include occasional hard-shelled marine foods, which along with the shells offered on the substrate help manage tooth growth. Most specimens take prepared foods readily, and no particular feeding-acclimation difficulty is associated with the species.

Mysis Shrimp Vitamin-Fortified Brine Shrimp Chopped Shrimp Chopped Fish Squid Clam Meat Frozen Carnivore Preparations Hard-Shelled Marine Foods
Wild fish are typically seen in small groups cruising just above reef-bottom terrain, ducking into caves when disturbed and at night. In the aquarium the species behaves as a semi-aggressive fish: confident, curious, and quick to assert itself over favored shelter. Keep only one triggerfish per system unless the two fish are an established mated pair, and add this fish after the other residents are settled so it does not claim the entire tank as its own. Very docile or slow-moving tankmates are poor choices; fishes of similar size and disposition fare much better.

Coral compatibility is generally good, and soft and stony corals are usually left alone, but this fish should be treated as reef safe only with caution. Ornamental shrimp, sea urchins, feather-duster worms, and small fishes are all at risk of being eaten, so a reef stocked with delicate mobile or exposed invertebrates is not an appropriate home. In a large, coral-focused display without prized cleaner shrimp or diminutive fishes, it can be a striking and manageable centerpiece.

FAQ

Frequently Asked Questions

About the Gold Back Triggerfish

  • How large an aquarium should I plan for?
    Plan on at least 250 gallons for an adult. A fish approaching 14 inches needs substantial open swimming room along with caves built into the rockwork.
  • Will it eat my corals or invertebrates?
    Soft and stony corals are usually not targeted, but ornamental shrimp, sea urchins, feather-duster worms, and small fishes may be eaten. Treat it as reef safe with caution rather than invertebrate-safe.
  • What should I feed it?
    Offer varied meaty foods such as mysis, fortified brine shrimp, chopped shrimp, fish, squid, and clam two or three times daily. Its natural diet is zooplankton, and occasional hard-shelled foods help wear the teeth.