Amazon leaf fish
Monocirrhus polyacanthus
One of the most extraordinary ambush predators in fishkeeping: the compressed body, brown livery with veining, and small chin barbel perfectly imitate a dead leaf. Swims slowly at an oblique head-down angle, drifting with the current toward prey, which it inhales with a lightning-fast accordion-like mouth expansion — capable of swallowing prey up to 2/3 of its own length. For experienced aquarists only: requires live food (nearly impossible to adapt to frozen), acidic, pristine water, species-only tank. A pure observation species.
Température de l’eau
25 - 28 °C
Valeur du pH
5.5 - 6.5
Type d'eau
Eau douce
Niveau dans le bac
Milieu
Taille adulte
8 cm
Volume minimal du bac
>= 75 L
Groupe minimal
>= 1
GH
1 - 5 dGH
KH
1 - 2 dKH
TDS
25 - 95 ppm
Conductivité
39 - 148 uS/cm
Description de l'espèce
Geographical Origin and Habitat: Amazon and Orinoco River Basin (Peru, Brazil, Venezuela). Exclusive to very slow swamps and "Blackwater" rivers saturated with dead lianas, fallen trees and decaying plant debris.
Taxonomy and Morphology: South American Leaf Fish (Monocirrhus polyacanthus). Mimetic evolution par excellence. The body is flat, perfectly leaf-shaped; it even has a rigid barbel on the chin that simulates the "stalk" of a dead leaf.
Social Behavior: Immobile ambush predator. Spends entire weeks floating upside down (obliquely) imitating a dead leaf moved by the current, waiting for a small unaware fish to approach.
Coloration and Sexual Dimorphism: Perfect camouflage: dry leaf brown or ochraceous yellow, with black mottling mimicking plant necrosis. Can lighten or darken to blend in with the decor. Sexes are indistinguishable.
Soins, reproduction et cohabitation
Aquarium Setup: Extreme leaf biotope (Species Tank 80 cm / 32 inches). Lighting reduced to zero, peat in the filter, dark tea-colored water. Bottom covered with catappa/oak leaves and intricate twigs in mid-water.
Diet and Feeding: Obligate piscivore (Lethal starvation 1). Will ALWAYS refuse any dry or dead feed (even if waved with tweezers). MUST be fed daily with live feeder fish (Guppies, Neons) or live ghost shrimp (Caridina) that fit entirely into its extensible tube mouth.
Water Quality: Very delicate (Lethal starvation 2). Requires very pure water while tolerating organic nitrates (but zero ammonia). The marked acidity (Ph 5.5-6.0) protects its skin lacking resistant scales from deadly fungal infections.
Compatibility and Cohabitation: It is not a community fish. Must be alone or with other Leaf fish. Any fish under 4 cm (1.5 inches) will be inhaled. Any aggressive fish (or sucking pleco) will annoy it to death.
Aquarium Breeding: The male and female mate depositing transparent eggs (up to 300) under a broad leaf of Nymphaea. The male fiercely guards the eggs by fanning them.
Risks and Diseases: The ethical/economic nightmare. This fish is the despair of unprepared aquarists: it literally starves to death if you do not provide it with a constant and expensive supply of LIVE small bait fish every single day.
Origine et répartition géographiques
Amazon and Orinoco River Basin (Peru, Brazil, Venezuela). Exclusive to very slow swamps and "Blackwater" rivers saturated with dead lianas, fallen trees and decaying plant debris.
Origine
Amazonie, Orénoque et Guyanes
Profil de poisson
- Tempérament
- Peaceful
- They have a lethargic, highly secretive, and perfectly methodical temperament. They are the ultimate ambush predators, relying entirely on their masterful camouflage to wait for prey to drift too close. They are fascinating to observe but require a highly dedicated aquarist willing to cater to their strict dietary and environmental needs.
- Régime alimentaire
- Carnivore
- They are obligate piscivores that will almost exclusively only accept live fish as food. Weaning them onto frozen meaty foods like bloodworms is extremely difficult and often unsuccessful. A steady, safe, and disease-free supply of live feeder fish or live ghost shrimp is absolutely mandatory for their long-term survival.
- Espérance de vie
- 5-8 years
- Taille adulte
- 8 cm
- Ratio des sexes
- Pair
- Visual sexing is virtually impossible outside of the breeding season when the female may appear slightly rounder. They are generally peaceful towards their own kind and can be kept in small groups if the tank is large enough. A group of three to five individuals increases the chances of a pair forming naturally.
- Fréquence d'alimentation
- Twice daily
- Due to their slow metabolism and inactive lifestyle, they do not need to be fed every day. Feeding them a suitably sized live prey item every two to three days is generally sufficient to keep them healthy. Overfeeding can lead to digestive issues and foul the pristine water conditions they require.
- Charge biologique
- Low to Medium
- The Amazon Leaffish produces a low bioload as it is small, inactive, and feeds infrequently. However, they demand exceptionally pristine water quality with zero ammonia or nitrites to survive. Strong biological filtration is necessary, but the physical flow must remain extremely low to accommodate their needs.
- Courant
- Stagnant
- They require almost completely stagnant water to mimic the quiet, leaf-littered pools of the Amazon basin. Even moderate currents will exhaust them and disrupt their delicate camouflage behavior. Gentle air-driven sponge filters are the ideal filtration method for this sensitive species.
- Risque de saut
- No
- Reproduction
- Substrate spawner
- Breeding the Amazon Leaffish is a rare and highly prized accomplishment in the aquarium hobby. They are substrate spawners, typically laying their eggs on the underside of broad plant leaves. The male will fiercely guard the eggs and fan them with his fins until they hatch.
- Compatibilité et compagnons
- Highly aggressive
- They are highly specialized ambush predators that will swallow any fish that fits into their surprisingly large, protrusible mouths. They must be kept in a species-only setup or with peaceful, heavily armored bottom dwellers like small Plecos. They should never be kept with aggressive fish that will outcompete them or stress them out.
- Niveau dans le bac
- Middle
- They utilize all levels of the aquarium, orienting themselves vertically or at odd angles to perfectly mimic a dead, drifting leaf. They require dense vegetation, floating plants, and abundant leaf litter on the substrate to feel secure. Without these elements, their camouflage fails, and they will suffer from extreme stress.
Modèles et paramètres scientifiques
FishBase
Fenêtre sur les données scientifiques officielles de l’espèce
FishBase v25.04Données synchronisées le : 15/06/2026
- Niveau trophique
- 4,2 ± 0,73 se
- Singularité phylogénétique (PD50)
- 1.0312
- Relation bayésienne longueur-poids
- a = 0.02042, b = 3.02
- VulnérabilitéVulnérabilité faible (10 / 100)
Galerie d'images
Images sous licence liées à l'espèce ou, lorsqu'elles sont indiquées, au taxon représentatif le plus proche.
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