Spot-tail Butterflyfish

Spot-tail Butterflyfish

The Spot-tail Butterflyfish (Chaetodon ocellicaudus) is a handsome, disc-shaped butterflyfish — bright yellow over much of the body with fine chevron lines, a black eye-band and saddle, and a distinctive dark spot near the tail base that gives it its name. Closely resembling the similar spot-banded butterflyfish, it is an elegant but demanding fish, with the coral-leaning diet typical of many Chaetodon that makes it a challenge for the experienced marine keeper.

Beautiful as it is, its feeding habits call for real caution in a reef.

Natural Habitat & Origin

Chaetodon ocellicaudus is found in the western Pacific, where it lives on coral-rich reefs, often in pairs, feeding on coral polyps and small invertebrates. It stays close to the coral on which it depends.

In the aquarium it needs a mature system with abundant live rock for foraging and shelter, calm surroundings, and time to settle.

Care Requirements

Maintain stable marine conditions: salinity around 1.024–1.026, pH 8.1–8.4, and a temperature of about 24–26°C (75–79°F). Reaching about 14 cm (5.5 inches), it suits a tank of around 280 litres (about 75 US gallons) or more with plenty of rockwork. Pristine, stable water quality and a peaceful environment are essential for this sensitive fish.

Diet & Feeding

The Spot-tail Butterflyfish is an omnivore that, in the wild, feeds substantially on coral polyps along with small invertebrates — making it a difficult feeder in captivity. Establishing it on prepared foods is the central challenge: tempt it with frozen mysis and enriched brine shrimp, finely chopped seafood, and specialised butterflyfish preparations, fed frequently, and lean on a mature, microfauna-rich tank. A thin, non-feeding specimen needs prompt, patient attention.

Behavior & Temperament

It is a peaceful, somewhat shy fish that mixes well in a calm community and is often kept as a pair. It rarely troubles other fish and spends its time foraging over the reef. Avoid aggressive or fast tankmates that will outcompete it for food or keep it hidden.

Tank Mates

Good companions are other peaceful marine fish — tangs, peaceful wrasses, anthias, cardinalfish and similar. In a reef, treat it with real caution: as a coral feeder it is not reef-safe and will nip stony and soft coral polyps, so it is best in fish-only systems, or accepted as a risk by keepers prioritising the fish over their corals.

Breeding

Chaetodon ocellicaudus is a pelagic spawner with planktonic larvae and is not bred in the home aquarium. Trade specimens are wild-collected.

Common Health Issues

The main challenge with this species is establishing it on prepared foods; many losses stem from a fish that will not feed adequately on a coral-free diet. Like all marine fish it is also susceptible to marine ich (Cryptocaryon irritans) and marine velvet (Amyloodinium ocellatum), particularly when stressed. Quarantine new arrivals carefully, keep water quality pristine and stable, and choose a specimen you have seen feeding. Given a mature tank and patience, it is an elegant but demanding fish for an experienced keeper.