South American Leaffish Species Profile

Characteristics, Origin, and Helpful Information for Hobbyists


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The unique South American Leaffish, or Amazon Leaffish, is a very interesting fish for the classroom or for the many aquarium keepers who wants a conversation piece. The South American Leaffish gets its name because it looks remarkably like an actual dead tree leaf. It is, however, a challenging freshwater fish to own, and it can be expensive as well. If you commit to owning one of these remarkable and rare ambush predators, you will need to fully embrace the challenge of a truly unusual fish.

Species Overview

Common Names: South American Leaffish, or Amazon Leaffish,

Scientific Name: Monocirrhus polyacanthus

Adult Size: 3-4 inches

Life Expectancy: 5 to 8 years


Family Polycentridae
Origin Amazon and Rio Negro Basins
Social Aggressive
Tank Level All
Minimum Tank Size 20 to 25 gallons
Diet Carnivore
Breeding Egg layer
Care Moderate to difficult
pH 6.0 to 6.5
Hardness 2 to 5 dH
Temperature 77 to 82 F (25 to 28 C)

Origin and Distribution

The South American Leaffish hails from the Amazon River basin in the countries of Peru, Brazil, Bolivia, Columbia, and Venezuela. It lives in shallow water where it hides among the vegetation in the riverbed, facing downward. Hidden from its prey by its surroundings, its camouflaged body, and its transparent fins, these fish are nearly undetectable until they attack.

Colors and Markings

The South American Leaffish looks extraordinarily like a dead leaf, floating among the vegetation toward the bottom of a tank. Like a leaf, it is small, oval-shaped, and flat from side to side; both its anal and dorsal fins are spiny, creating a body margin of jagged edges, like a perfect leaf outline.

This fish is yellow to brown with random markings as well as three lines running from the eye to the belly, from the mouth to the caudal fin, and from the eye to the dorsal fin, resembling the veins of the leaf. Many have a quarter-inch-long flap of skin protruding from the lower lip that looks like the stem of a leaf. It has a huge mouth relative to its size.

So good is its camouflage that even in a net with assorted dead leaves and twigs, it is likely to be returned to the water unseen — unless it moves. To complete the deception, the only fins that normally move, the pectorals and the rear tips of the dorsal and anal fins, are transparent and nearly invisible even when in motion.

An even more impressive aspect of the South American Leaffish is its uncanny ability to alter its camouflage while lying in wait for prey. Like a chameleon, its colors may change in order to blend in more perfectly with its background whether in the wild or in captivity.


An ambush predator, the leaffish lies in wait of any prey that will fit into its very large mouth. This fish can eat its own weight in live fish every day. Even though it is only about three inches full-grown, it will clean out your entire community aquarium tank in a week if the other fish are smaller than it is.  For this reason, it is best to keep this species on its own. If you do want to include other fish in the tank, choose larger, more robust and aggressive species such as the Armored Catfish or medium-sized loricariids.

South American Leaffish Habitat and Care

To thrive, the South American Leaffish needs soft water and dim light. Floating plants can help to recreate the fish's natural habitat and keep harsh light from filtering down. Because this fish hunts in ambush and is easily frightened, it also needs plenty of large-leafed plants and driftwood as objects to hide behind. Water filtration in the aquarium should be sufficient to maintain good water quality, but keep the water flow as still as possible.

South American Leaffish Diet and Feeding

Leaffish do well in an aquarium as long as they eat live fish as their main diet. In order for this fish to be kept alive, each fish must be fed the equivalent of at least three adult guppies per day, or they will quickly weaken and die. Guppies are eagerly eaten, but feeding large, live food can be costly. In some places, such as the southern states, there is an abundance of small native fish that can be caught and fed to the Leaffish.

Leaffish typically swim or hang in the water at an un-fish-like, head-down angle. While this clever rouse gives the three-inch leaffish wonderful protection from larger predatory fish, the main value of the camouflage is as an aid in capturing smaller fish. The leaffish may drift with the current until an unsuspecting smaller fish swims near, or it may sidle ever so slowly up to a fish until its mouth is almost touching. Then it quickly opens its enormous mouth to create a vacuum that sucks the smaller prey inside.

Gender Differences

There are few differences between males and females, though females will appear more plump during the spawning season. The male also has slightly larger fins.

Breeding the South American Leaffish

This species is not particularly difficult to breed; the challenge is not so much providing special conditions, as it is the luck of finding a pair that happens to be ready to breed. If they are ready to breed and if there is a broadleaf plant such as an Amazon Sword Plant, females will lay eggs on the underside of the leaf or the underside of an overhanging stone. After the female carefully deposits her eggs, the male fertilizes them. Each egg is attached to the leaf or stone by a short thread. Hence, the large glassy eggs are all raised slightly off the spawning site. The eggs will be tended to closely by both parents and hatch in three to five days.

The male leaffish stays close to the eggs, carefully fanning water over the eggs. After hatching, the babies remain attached to the spawning site by the egg thread for another week. Once they are free-swimming, baby leaffish act much like their parents, remaining still most of the time. At first, young leaffish eat small aquatic microorganisms, but by the time they have grown to a half-inch, they are able to eat small fish the size of baby guppies or brine shrimp.

The fry (baby fish) are transparent for about two weeks and will graze on infusoria that exists on mature plants and rocks in the aquarium. After two weeks the fry should be removed and separated since they grow at different speeds; larger fry will eat smaller fry as soon as they can fit the smaller fry into their mouths.

Leaffish fry must be fed plenty of daphnia, mosquito larva, brine shrimp and if available, guppy fry for fastest growth. The fry are covered with white specks up until about two months of age. They appear to have an Ich infection, but this is just natural coloring for a fry of this age. After two to three months, the fry will obtain adult coloration and be ready to eat larger fish. At this point, they must be separated further by size.

More Pet Fish Species and Further Research

Obligate predators are intensive and costly fish to keep and feed, but if you’re interested in similar species, check out:

Check out additional fish species profiles for more information on other freshwater fish.