Siamese Blenny

Siamese Blenny

The Siamese Blenny (Meiacanthus smithi) — more commonly known as Smith's fang blenny or the disco blenny — is an elegant, easygoing reef fish from the eastern Indian Ocean. Slender and pale with a dark dorsal margin and a graceful trailing tail, it hovers and swims in open water far more than most bottom-hugging blennies, giving it a presence in the aquarium out of proportion to its small size.

Like all members of the genus Meiacanthus, it carries a clever defence: venomous fangs used purely to deter predators. This makes it both reef-safe and remarkably secure in a community — would-be predators quickly learn to leave it alone — and it is a hardy, beginner-friendly fish that is widely captive-bred.

Natural Habitat & Origin

Meiacanthus smithi is found on coral reefs of the eastern Indian Ocean, around Sri Lanka, Sumatra and the Andaman and Nicobar Islands. It frequents reef slopes where it swims and hovers in the water column, darting to shelter in rock and coral when threatened.

In the aquarium it appreciates live rock with crevices to retreat into, combined with open swimming space where it can cruise mid-water as it would on the reef.

Care Requirements

Keep it in 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 only about 8.5 cm (3.3 inches), it is well suited to tanks of around 75 litres (20 US gallons) and up. A secure lid is recommended, as active mid-water blennies can jump.

Its hardiness and small size make it an excellent choice for beginners and nano-to-mid reefs alike.

Diet & Feeding

The Siamese Blenny is an omnivore that feeds on zooplankton and small organisms in the water column along with some algae. It readily accepts aquarium foods, so offer a varied diet of frozen mysis and brine shrimp, quality marine flakes and small pellets, and foods with marine algae content. Feed small amounts a couple of times daily; it is an unfussy, reliable feeder.

Behavior & Temperament

This is a peaceful, confident fish that coexists well with a wide range of tankmates and is rarely harassed thanks to its venomous defence. It can be kept singly; as with many fang blennies, keeping multiples together risks squabbling unless the tank is large or they are a known pair. It spends much of its time hovering and cruising in open water, a lively and watchable community member.

Tank Mates

The Siamese Blenny suits peaceful and semi-aggressive reef communities: clownfish, gobies, cardinalfish, anthias, smaller wrasses and similar. Because it is protected by its fangs, even larger fish tend to leave it be — though very large predators are still best avoided. It is fully reef-safe and will not harm corals or ornamental invertebrates.

Breeding

Meiacanthus blennies, including M. smithi, are bred commercially, and captive-bred specimens are regularly available. Pairs deposit eggs in a sheltered crevice or cavity, which the male tends until hatching. Rearing the larvae is achievable for committed hobbyists with appropriate small live foods, making fang blennies a popular group for marine breeding projects.

Common Health Issues

The Siamese Blenny is hardy and undemanding, but like all marine fish it can be affected by marine ich (Cryptocaryon irritans) and marine velvet (Amyloodinium ocellatum), particularly when newly imported or stressed. Quarantine new arrivals, keep water quality stable, and secure the lid against jumping. Handle with a little care — its fangs are a defensive tool — and it will reward you as one of the easiest and most engaging small marine fish in the hobby.