American Leaffish
(Monocirrhus polycanthus)

South American leaffish or Monocirrhus polyacanthus belong to the family Nandidae. The leaffish is obviously indigenous to South America. It is also referred to by the name Amazon leaffish.

A commonality to unusual looking fish is that their name typically describes the features that make them unique.  The leaffish’s peculiarly shaped body and patchy coloration resembles a leaf in the fall. Their bodies are rather flat and wide which contributes to the resemblance. Even the way that they swim seems to mimic a leaf falling through the air.

The Leaffish is an aggressive predator. Their diet consists mainly of other fish. In the wild they will lay among the substrate foliage with their heads pointed down. Their distinctive color palette makes it hard to distinguish them from a dead leaf. The leaffish has the unique ability to change colors to better camouflage itself amid the foliage. It will approach its prey using its transparent pectoral fins which are nearly undetectable to its victim. It will then open its abnormally large mouth and suck in its dinner. They will also dine on worms, insects and insect larvae in the wild, especially when they are still small.

Given their predatory nature it is not recommended that they be kept in a community tank. If you decide to do so, their tank-mates must be a robust, less timid fish of similarly or slightly larger size. Once again this fish will swallow smaller species whole. Leaffish are relatively small. They grow to about 3 inches in length. Keep this in mind when choosing their potential roommates. They will also require subdued lighting with lots of foliage to hide in.

Like most South American varieties, the leaffish is accustomed to slightly acid water; pH 6.8. Water temperatures can vary from 74-80 °F.

Males and females are hard to distinguish from one another unless it is breeding time. In their spawning cycle the female has a visible ovipositor near her anus used for laying eggs. Because of their natural ability to camouflage themselves, spawning often takes place in community tanks.

Leaffish may be induced to spawn by establishing a properly controlled environment. As with any fish a breeding tank is recommended.  An increase in water temperature will simulate spawning season. You will also want your breeding tank water to be soft and slightly acidic. If you live in a region where the tap water is hard use bottled or reverse-osmosis filtered water. PH levels can be altered chemically. Or there is a completely organic way to increase acidity levels. The breeding tank’s water can be filtered through peat. The peat will release humic acid into the water raising the acidity level. You will also want subdued lighting and plenty of foliage.

The couple is about to spawn when you observe them cleaning off a rock or other flat surface to deposit their eggs on. After spawning the male will become the caregiver. The female is prone to harass the male and should be removed form the tank.

The fry will hatch in 60-90 hours depending on water temperature. Leaffish fry are voracious eaters and will consume their body weight on a daily basis. They will develop at different rates. Larger fry should be separated from smaller fry to prevent cannibalism.

Fry can be fed newly hatched shrimp brine, liquid rotifers or powdered fry food formulated for egg laying fish.