Amazon Leaf Fish

Monocirrhus polyacanthus

Other

A master of camouflage that perfectly mimics a dead leaf drifting in the water. This species is an extreme ambush predator with a protruding jaw that can swallow prey up to 75% of its own size. It is a 'specialist' species because nearly all specimens require live food (small fish/shrimp) and refuse dry or frozen foods. Requires acidic, blackwater conditions and zero flow.

At a Glance

Adult Size8 cm
Body ShapeCompressed
Growth RateModerate
TemperamentPeaceful
Water TypeFreshwater Only
Flow PreferenceLow
Waste OutputHigh
StockingSolo or group

Tank Requirements

Minimum Volume75 L
Minimum Length60 cm
FlowLow
Water TypeFreshwater Only
Must-Haves in the Tank
Leaf Litter/BlackwaterPlants - Densely coveredDriftwood (Digestion/Hiding)Plants - Floating

Water Parameters

Temperature2329°C
pH56.8
Hardness08 dGH

Temperament & Compatibility

Aggression LevelPeaceful
2/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least1 (solo is fine)
Max per TankNo limit
Can Live Alone?Yes
Behavior Traits
Piscivore (Eats small/nano fish)Shrimp EaterFry PredatorShy / Slow Moving (Easily Stressed)Nocturnal

Available Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Standard

The wild-type form. Color changes to match surroundings (brown, yellow, gray). Must be kept with tankmates too large to be swallowed, or alone. Extremely peaceful towards anything it cannot eat.

Differs in 1 trait from base species

Behavior Traits
Piscivore (Eats small/nano fish)Shrimp EaterShy / Slow Moving (Easily Stressed)

Amazon Leaf Fish Care Summary

The Amazon Leaf Fish, scientifically known as Monocirrhus polyacanthus, belongs to the Other family group. Adults reach a maximum size of approximately 8 cm and have a compressed body shape with a moderate growth rate. Classified as peaceful, this species primarily occupies the mid-level and surface zones of the aquarium and produces a high level of biological waste.

To thrive, the Amazon Leaf Fish requires a freshwater only aquarium with a minimum volume of 75 litres and a tank length of at least 60 cm. Water temperature should be maintained between 23°C and 29°C, with a pH range of 56.8 and a general hardness of 08 dGH. A low water flow is preferred. To replicate their natural habitat, the tank should include leaf litter/blackwater, plants - densely covered, driftwood (digestion/hiding), and plants - floating.

Amazon Leaf Fish can be kept singly or in a group, making them flexible additions to most setups. Keepers should be aware that this species will prey on fish small enough to fit in its mouth, is not safe with ornamental shrimp, and is primarily active at night or during twilight hours. The Amazon Leaf Fish is typically available in one standard form.


Similar Species

Leopard Bushfish (Ctenopoma)

Ctenopoma acutirostre

Anabantoids
15 cm Mostly Peaceful

A fascinating, ancient African anabantoid that mimics a dead leaf to ambush prey. They possess a surprisingly large, extendable mouth. While slow-moving and generally peaceful towards fish too large to swallow, they are efficient predators of small fish and invertebrates. They are crepuscular (active at twilight) and require structure (wood/plants) to feel secure.

Bumblebee Goby (Brackish)

Brachygobius xanthozonus

Gobies & Gudgeons
4.5 cm Mostly Peaceful

A miniature, bottom-dwelling goby famous for its striking black and yellow stripes. While they are often sold as freshwater fish and can survive in it temporarily, they are highly susceptible to fungal infections in fresh water and truly require a brackish setup (SG 1.002-1.005) to thrive long-term. They are notoriously picky eaters, often ignoring flakes in favor of live or frozen foods (like bloodworms or brine shrimp).

Amazon Puffer

Colomesus asellus

Puffers
8 cm Mostly Peaceful

One of the few truly freshwater, community-safe pufferfish. Native to the Amazon basin, these energetic swimmers are known for their bumblebee-like stripes and erratic swimming patterns. Unlike most puffers, they are social and prefer to be kept in groups. CRITICAL WARNING: This species has the fastest-growing teeth of any puffer. They REQUIRE a daily diet of hard-shelled foods (snails, clams, crustaceans) or they will require manual dentistry (trimming) to prevent starvation.

Neon Tetra

Paracheirodon innesi

Characins
4 cm Peaceful

One of the most iconic freshwater fish in the hobby, famous for its striking iridescent blue and red stripes. Originally from the blackwater streams of the Amazon basin, they prefer slightly cooler water than many tropical fish and must be kept in schools to thrive, display natural behaviors, and feel secure.

Black Ghost Knifefish

Apteronotus albifrons

Oddballs
40 cm Semi-Aggressive

A fascinating nocturnal predator native to the Amazon basin. It lacks a dorsal fin and moves via a continuous undulating ventral fin, allowing it to swim backwards as easily as forwards. It generates a weak electrical field to navigate and hunt in the dark. Scaleless and highly sensitive to medications, it requires smooth hiding places (like PVC pipes or smooth driftwood). Will consume any fish small enough to fit in its surprisingly large mouth.

Freshwater Angelfish

Pterophyllum scalare

Cichlids - South American
15 cm Semi-Aggressive

The most iconic South American Cichlid, known for its distinct arrowhead shape and majestic fins. While domestic strains are hardy, they remain cichlids: they are semi-aggressive predators that will eat any fish small enough to fit in their mouths (like Neon Tetras). They form loose shoals as juveniles but pair off and become territorial as they mature. Height is more important than length for this species.