Juvenile Emperor Angelfish - Medium (Pomacanthus imperator)

The Juvenile Emperor Angelfish (Pomacanthus imperator), also sold as the Imperator Angelfish, is a medium juvenile still wearing its deep navy body and the bright white and electric blue rings that circle toward the tail. Over time it trades those rings for the adult look of yellow and blue horizontal stripes with a dark mask, one of the most dramatic color changes in the hobby. It is a semi-aggressive, intermediate-level fish that is not reef safe and grows large, so it belongs in a big fish-only or fish-with-live-rock system. Browse the rest of our saltwater livestock and supplies and our full fish selection while you plan.

Care Guide

• Tank size: 180 gallons minimum for an adult, 220 gallons or more preferred. Emperors reach around 15 inches. A medium juvenile can grow out in a smaller established tank for a while only if the larger tank is already planned.
• Mature system: choose a stable, well-filtered tank with plenty of live rock for grazing and caves for cover. Large angels are messy eaters, so strong filtration and regular water changes matter.
• Water parameters: 72 to 78°F, pH 8.1 to 8.4, salinity 1.020 to 1.025, alkalinity 8 to 12 dKH.
• Feeding: omnivore. Wild fish eat a lot of sponge, so offer a frozen angel formula that contains sponge, like SFBB Angel & Butterfly Cubes or Hikari Bio-Pure Mega-Marine Angel, plus seaweed and meaty foods like PE Mysis. Feed two to three times daily.
• Settling in: a new juvenile can stay shy for the first few days. Keep the lights low after you bring it home, offer several foods, and give it time to start exploring.
• Quarantine at home: we recommend quarantining any new fish in a separate tank at home before it joins your display.

Specifications

Compatibility

Not reef safe. Emperors pick at large-polyp stony corals, soft corals, zoanthids and clam mantles, so a fish-only or fish-with-live-rock tank is the better home.

It does best with robust tank mates of a similar size, such as the Powder Brown Tang, Sailfin Tang, Blue Throat Trigger and Arc Eye Hawkfish. Keep one large angelfish per tank unless the system is very large and both go in together. Skip very small, timid fish that a growing Emperor could bully.

Recommended Foods & Supplies

• SFBB Angel & Butterfly Cubes, a sponge-based frozen staple
• Hikari Bio-Pure Mega-Marine Angel for variety in the frozen diet
• Brightwell AngeLixir to soak foods and tempt a new arrival to eat
• Two Little Fishies SeaVeggies Purple Seaweed for daily greens
• Piscine Energetics PE Mysis for the meaty part of the diet
• Innovative Marine AccuDrip Acclimator for a gentle drip acclimation at home

FAQ

When will it change into adult colors?
Usually as it grows through the 3 to 5 inch range, and the change happens gradually. Rings give way to yellow and blue stripes, so you will see in-between patterns along the way.

Can I start it in a smaller tank?
A juvenile can grow out in an established tank of 100 gallons or more for a short time, but it will need 180 gallons or more as an adult. Only start small if the upgrade is already planned.

Can I keep it in a reef tank?
We do not recommend it. Emperors often nip corals and clam mantles, and that habit can start at any age.

Can I keep it with other angelfish?
Usually one large angel per tank is the safest plan. Only very large systems can handle more, and they should go in at the same time.