Monodactylidae
Monodactylidae, commonly known as the “fingerfishes” or “monodactylids,” is a family of perciform fish belonging to the order Perciformes. They are characterized by their unique flattened bodies, compressed laterally, giving them a distinctive “finger-like” appearance. Their small mouths, often with a protruding lower jaw, are adapted for feeding on small crustaceans and insects. This family consists of two genera, Monodactylus and Schuettea, with a total of eight recognized species.
Distribution and Habitat
Monodactylids are distributed throughout tropical and subtropical regions, primarily inhabiting brackish waters, estuaries, and coastal areas with abundant vegetation. Their adaptability allows them to tolerate fluctuating salinity levels, a key factor in their success in these transitional environments. While they can occasionally be found in freshwater habitats, they are not truly freshwater fish and require some level of salinity for survival.
Physical Characteristics
The defining feature of monodactylids is their laterally compressed body shape, resembling a flat, thin finger. This adaptation likely evolved for maneuverability in dense vegetation, allowing them to navigate through aquatic plant life with ease. Their fins are relatively small, with the dorsal fin being continuous and elongated. They exhibit a wide range of colors, often displaying vibrant yellow, orange, or blue hues with dark markings or spots.
Diet and Behavior
Monodactylids are primarily insectivores, feeding on a diet consisting mainly of insects, crustaceans, and algae. Their small mouths, equipped with delicate teeth, are well-suited for capturing these small prey items. They are generally solitary fish, often found hiding among vegetation or near submerged branches, waiting to ambush passing prey.
Reproduction
Monodactylids exhibit a range of reproductive behaviors, with some species being known for their nest-building habits. The males of some species prepare elaborate nests within vegetation, attracting females for spawning. The females lay eggs, and the males typically guard the nests until the eggs hatch.
Species
The following is a list of the eight recognized species within the Monodactylidae family:
- Monodactylus argenteus (Linnaeus, 1758)
- Monodactylus falciformis (Lacepède, 1801)
- Monodactylus kottelati (Tan & Ng, 2005)
- Monodactylus lacepedii (Cuvier, 1829)
- Monodactylus lineatus (Cuvier, 1829)
- Monodactylus sebae (Cuvier, 1829)
- Schuettea psilochir (Günther, 1861)
- Schuettea vespertina (Günther, 1861)