Fourmanoir's Blenny
Ecsenius fourmanoiri
A small and peaceful blenny from the Southwest Pacific, characterized by a bicolored body and its characteristic habit of perching on rocks and corals.
Température de l’eau
22 - 26 °C
Valeur du pH
8.1 - 8.4
Type d'eau
Marin
Niveau dans le bac
Fond
Taille adulte
5,5 cm
Volume minimal du bac
>= 60 L
Groupe minimal
>= 1
Description de l'espèce
Geographical Origin and Habitat: Endemic to the Southwest Pacific, mainly recorded in the Loyalty Islands, New Caledonia, and Vanuatu. It inhabits shallow coastal coral reefs and protected outer reefs, usually at depths between 1 and 15 meters, preferring vertical walls and rock crevices exposed to moderate currents.
Taxonomy and Morphology: Belongs to the family Blenniidae, genus Ecsenius. Features an elongated and scaleless body typical of blennies, with a rounded head and large mobile eyes situated high up. Reaches a maximum standard length of only 5 centimeters, making it an excellent candidate for small aquariums.
Social Behavior: Primarily a solitary and territorial species towards other blennies or species of similar shape and color. It spends most of its time perching on rocks or corals, scanning its surroundings. It is peaceful towards unrelated species and does not disturb other aquarium inhabitants.
Coloration and Sexual Dimorphism: Displays a distinct bicolored pattern: the front and upper part of the body is dark, fading from smoky grey to black, while the rear and lower part is light grey or whitish. It features yellow or orange accents at the base of the dorsal fin and a thin orange line around the eyes. Sexual dimorphism is not prominent, except that breeding males may display slightly more intense coloration.
Soins, reproduction et cohabitation
Aquarium Setup: Requires a tank of at least 80 liters rich in live rock. It is essential to arrange numerous crevices, small holes, and rock fissures where the fish can establish its territory and hide. It appreciates the presence of small corals or rocky shelves to perch on and scan the area.
Diet and Feeding: Primarily a herbivorous and detritivorous species. In the wild, it feeds on the algal film covering the rocks. In the aquarium, it requires a plant-based diet rich in spirulina, herbivore flakes or pellets, supplemented occasionally with small frozen foods such as cyclops, brine shrimp, and mysis to vary the diet.
Water Quality: Maintain standard marine parameters: water temperature between 22 and 26 °C, pH stable between 8.1 and 8.4, and specific gravity at 1.020-1.025. Efficient filtration and moderate water movement are ideal to simulate its native coastal currents.
Compatibility and Cohabitation: An ideal fish for peaceful reef aquariums. It can coexist with a wide range of small fish (gobies, pipefish, peaceful damselfish). Avoid housing with other blennies of the genus Ecsenius in the same tank, unless the tank is very large, to prevent territorial disputes.
Aquarium Breeding: Oviparous reproduction. It deposits eggs inside small crevices or empty shells. The male takes care of fertilization and guards the nest until the eggs hatch, showing a strong parental instinct during this period.
Risks and Diseases: A hardy species, but the primary risk is malnutrition if kept in aquariums lacking natural algae or if adequate vegetable food is not provided. It is sensitive to copper-based treatments, which should be avoided or used with extreme caution.
Origine et répartition géographiques
Endemic to the Southwest Pacific, mainly recorded in the Loyalty Islands, New Caledonia, and Vanuatu. It inhabits shallow coastal coral reefs and protected outer reefs, usually at depths between 1 and 15 meters, preferring vertical walls and rock crevices exposed to moderate currents.
Origine
Océans tropicaux et récifsAustralie, 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
- 5.5 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 fourmanoiri 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
- Peaceful
- The Ecsenius fourmanoiri 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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