Yellowtail Clown Blenny
Ecsenius melarchus
Featuring a dark body with a contrasting bright yellow-orange tail, this small marine blenny is an exceptionally beautiful and active choice for nano-reef tanks.
Température de l’eau
23 - 27 °C
Valeur du pH
8.1 - 8.4
Type d'eau
Marin
Niveau dans le bac
Fond
Taille adulte
6 cm
Volume minimal du bac
>= 60 L
Groupe minimal
>= 1
Description de l'espèce
Geographical Origin and Habitat: Native to the Western Central Pacific, mainly in Indonesia, the Philippines, and Papua New Guinea. It is predominantly found on tropical coral reefs, preferring shallow, sheltered patch reefs, lagoons, and outer reef slopes rich in Acropora branching corals, at depths between 1 and 20 meters.
Taxonomy and Morphology: Belongs to the family Blenniidae, genus Ecsenius. It features an elongated, scale-less cylindrical body coated with protective mucus. It has small tentacles (cirri) above its eyes. Its mouth is inferior and equipped with comb-like teeth adapted for scraping algae. It reaches a maximum length of about 5-6 cm (2 inches).
Social Behavior: Solitary and highly territorial, especially intolerant of conspecific males or species with similar shapes and colors. It spends a lot of time perched on rocks or corals, scanning its territory and retreating into small holes at any sign of danger. It is generally peaceful toward tankmates from other families.
Coloration and Sexual Dimorphism: The base body color ranges from dark gray-brown to blackish, with a striking, bright orange-yellow patch covering the caudal fin and the posterior portion of the caudal peduncle. The eyes are highlighted by a distinct light blue or white line. Sexual dimorphism is not prominent, though males can be slightly larger.
Soins, reproduction et cohabitation
Aquarium Setup: Requires a mature marine aquarium of at least 80-100 liters (20-26 gallons), decorated with plenty of live rock to provide numerous caves, cracks, and small holes where it can establish its home. Live rock is also essential to grow the algae biofilm it feeds on. A tight-fitting lid is recommended to prevent jumping.
Diet and Feeding: A specialized herbivore (microphage). In nature, its diet consists of benthic algae and detritus scraped from rocks. In captivity, it must be provided with spirulina-based flakes or pellets, dried nori sheets, and frozen foods prepared for herbivorous marine fish. Occasional small crustaceans are accepted but should not be the staple.
Water Quality: Requires standard marine reef parameters: temperature between 24°C and 27°C (75°F - 81°F), pH between 8.1 and 8.4, salinity/specific gravity of 1.022-1.025, and carbonate hardness (dKH) between 8 and 12. Efficient filtration and protein skimming are necessary to keep nitrates and phosphates low.
Compatibility and Cohabitation: Compatible with most peaceful reef fish like clownfish, anthias, small gobies, and pipefish. Do not house with other Ecsenius species to prevent intense territorial fighting. It is generally reef-safe, though it might occasionally nip at SPS coral polyps if underfed.
Aquarium Breeding: Captive breeding is extremely rare. They are demersal spawners; adhesive eggs are laid in crevices or empty shells and guarded by the male until hatching. Raising the pelagic larvae requires live microscopic zooplankton (rotifers) in a separate culture setup.
Risks and Diseases: Robust once acclimated, but vulnerable to starvation in new, clean tanks lacking natural algae. Subject to marine ich (Cryptocaryon) and velvet (Oodinium) under stress. Ensure the fish is eating well.
Origine et répartition géographiques
Native to the Western Central Pacific, mainly in Indonesia, the Philippines, and Papua New Guinea. It is predominantly found on tropical coral reefs, preferring shallow, sheltered patch reefs, lagoons, and outer reef slopes rich in Acropora branching corals, at depths between 1 and 20 meters.
Origine
Océans tropicaux et récifsAfrique et MadagascarAsie du Sud et du Sud-EstAustralie, Nouvelle-Guinée et Océanie
Profil de poisson
- Tempérament
- Territorial
- They possess a charming and comical personality, often observing their surroundings with curious expressions from their perches. While generally peaceful, they can show territorial behavior towards new additions that compete for bottom space or algae grazing areas. They are usually ignored by larger, more active swimming fish, making them a wonderful and entertaining addition to a community reef tank. Once established, they become quite bold and visible.
- Régime alimentaire
- Herbivore
- In the wild, they graze heavily on microalgae and detritus found on live rock. In the home aquarium, their diet should consist primarily of vegetable matter, including spirulina, marine algae, and specialized herbivore preparations. They will also eagerly accept meaty foods like mysis shrimp and brine shrimp, which should be offered as supplementary nutrition. Supplying an abundance of mature live rock is highly beneficial.
- Espérance de vie
- 3-5 years
- Taille adulte
- 6 cm
- Ratio des sexes
- Solitary
- While they can be kept singly without any issues, keeping a mated pair or a small harem (one male with multiple females) can be attempted in larger aquariums. Males are generally highly territorial towards other males, so keeping multiple males in the same tank is highly discouraged. Providing ample hiding spots and visual breaks can help manage any aggression within a harem setup. It is best to introduce females before or simultaneously with the male.
- Fréquence d'alimentation
- Twice daily
- To mimic their natural grazing behavior, it is recommended to feed them small amounts multiple times a day. Providing continuous access to algae-covered rocks or supplemental nori sheets will keep them actively foraging and healthy. Feeding them at least two to three times daily ensures they receive adequate nutrition and maintain their body weight. Without frequent feeding, they may begin to harass corals.
- Charge biologique
- Low
- The Ecsenius melarchus produces a relatively small amount of waste, contributing minimially to the overall bioload of the aquarium. Regular water changes and standard filtration are typically sufficient to handle their waste output. They do not put a heavy strain on the biological filtration systems, making them suitable for mature reef tanks. Their small adult size means they consume less food and thus excrete less.
- Courant
- Strong
- They thrive in areas with moderate to strong water flow that simulates the turbulent conditions of their natural reef environment. Good water movement helps keep the live rock free of detritus and promotes the growth of the microalgae they feed upon. The flow should not be so overpowering that it prevents them from swimming or resting comfortably in their favorite crevices. Intermittent wave action is particularly appreciated.
- Risque de saut
- Yes
- Like many blennies, this species is known to be a prolific jumper, especially when first introduced to a new environment or if chased by aggressive tank mates. A tightly fitting lid or a fine mesh screen cover is absolutely essential to prevent them from jumping out of the aquarium. Even small gaps around equipment can provide an escape route, so thorough securing of the tank top is necessary. Startled fish will dart upwards instinctively.
- Reproduction
- Oviparous
- Breeding in the home aquarium is rare but not impossible, as they are substrate spawners. The male will typically prepare a crevice or an empty shell to serve as a nest, where he will court a female to deposit her eggs. Once the eggs are laid and fertilized, the male will guard the nest fiercely until the larvae hatch and enter the pelagic stage. Rearing the fry requires specialized tiny live foods like rotifers.
- Compatibilité et compagnons
- Reef safe
- The Ecsenius melarchus is generally peaceful towards most other tank mates, particularly those occupying different ecological niches. They are considered reef safe and will not bother corals or most invertebrates, though they might occasionally nip at clam mantles or large-polyp stony corals if underfed. Caution is strongly advised when keeping them with other blennies or fish with similar body shapes to avoid territorial disputes. They mix well with free-swimming fish.
- Niveau dans le bac
- Bottom
- This species is primarily a benthic fish, spending the majority of its time perching on live rock and the substrate. They are rarely seen swimming freely in the middle or upper levels of the water column unless they are dashing out to grab food. They will choose a favorite rock crevice or hole to use as a safe retreat, observing the tank from this vantage point. Their modified pectoral fins allow them to prop themselves up easily.
Modèles et paramètres scientifiques
FishBase
Fenêtre sur les données scientifiques officielles de l’espèce
FishBase v25.04Données synchronisées le : 15/06/2026
- Niveau trophique
- 2 ± 0 se
- Résilience
- Élevée (moins de 15 mois)
- Singularité phylogénétique (PD50)
- 0.5
- Relation bayésienne longueur-poids
- a = 0.00776, b = 3
- VulnérabilitéVulnérabilité faible (10 / 100)
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