TankBud

Swallowtail angelfish

Genicanthus melanospilos

Also known as Blackspot Angelfish, Spotbreast Angelfish, Japanese Swallowtail Angelfish

SaltwaterFish

Swallowtail angelfish (Genicanthus melanospilos)
Hectonichus · CC BY-SA 3.0

Care at a glance

Temperature
72–79°F
22–26°C
pH
8.1–8.4
Adult size
7.1 in
18 cm
Minimum tank
106 gal
400 L
Temperament
Mostly peaceful
Social behavior
Social
Swim level
Middle
Diet
Omnivore
Difficulty
Medium
Breeding
Hard
Rarity
Rare
Reef safe
Reef safe
Family
Pomacanthidae
Origin
Western Pacific, from Indonesia to Fiji, north to the Ryukyu Islands, south to Rowley Shoals and New Caledonia

Overview

The swallowtail angelfish is a plankton-eating angel that suits a reef tank. It is a step up from the easiest marine fish.

Did you know

The swallowtail angelfish is now produced in large captive-bred batches by a Palau-based aquaculture operation. For years before that, only a handful of wild-caught fish would show up in a shipment at a time.

Caring for the swallowtail angelfish

Give the swallowtail angelfish at least 106 gal (400 L), with open swimming space, varied rockwork and a bit of sandy bottom. The water should run at 72 to 79°F (22 to 26°C), with a pH of 8.1 to 8.4.

Feed small meals of mysis, finely chopped seafood and spirulina-based foods several times a day. As a planktivore, it leaves corals and clams alone.

It is mostly peaceful, but it can chase small, docile planktivores, so choose its tank mates with that in mind. Keep one male per tank. Multiple females are fine with him in a larger system.

Males show dark markings across the breast and a deeply forked, lyre-shaped tail. Females are paler, with different markings and no breast patch.

Good to know

The swallowtail angelfish, Genicanthus melanospilos, belongs to the marine angelfish family Pomacanthidae. The names blackspot and spotbreast angelfish come from the male's breast pattern. It is also sometimes called the Japanese swallowtail angelfish, after part of its range around the Ryukyu Islands.

In the wild

The swallowtail angelfish lives in the western Pacific, from Indonesia to Fiji. Its range reaches north to the Ryukyu Islands and south to Rowley Shoals and New Caledonia. It keeps to steep reef slopes, drop-offs, caves and boulder bases about 20 to 45 meters down. Coral growth there is mixed with open sand. Unlike most Genicanthus, it splits its time between picking plankton in midwater and foraging near the bottom.

Weekly picks

Tank mates

The swallowtail angelfish is a mostly peaceful, social species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does a swallowtail angelfish need?

A swallowtail angelfish needs at least 106 gal (400 L). It spends most of its time in the middle.

What temperature and pH does a swallowtail angelfish need?

A swallowtail angelfish is comfortable at 72–79°F (22–26°C) with a pH of 8.1–8.4.

What does a swallowtail angelfish eat?

A swallowtail angelfish eats small meals of mysis, finely chopped seafood and spirulina-based foods. Feed it several times a day.

How big does a swallowtail angelfish get?

An adult swallowtail angelfish reaches about 7.1 in (18 cm).

How can you tell a male swallowtail angelfish from a female?

Males have dark markings across the breast and a deeply forked, lyre-shaped tail. Females are paler, with different markings and no breast patch.

Related species