Monodactylidae is a family of

perciform Perciformes (), also called the Percomorpha or Acanthopteri, is an order or superorder of ray-finned fish. If considered a single order, they are the most numerous order of vertebrates, containing about 41% of all bony fish. Perciformes means " ...

bony fish commonly referred to as monos, moonyfishes or fingerfishes. All are strongly laterally compressed with disc-shaped bodies and tall anal and

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

s. Unusually for fish,

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number w ...

occur on their dorsal fins and sometimes on the anal fins. The pelvic fins are small, sometimes

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

. They are of moderate size, typically around in length, and ''Monodactylus sebae'' can be taller than it is long, measuring up to from the tip of the dorsal fin down to the tip of the anal fin. These long, scaly fins have given them the name "fingerfishes". Most are silvery with yellow and black markings; the juveniles are especially attractive, and most species are popular as aquarium fish. The family contains six extant species in two genera, ''Monodactylus'' and ''Schuettea''. They are distributed along the coastlines of Africa, India, and southern Asia, and as far west as Australia. Species of ''Monodactylus'' in particular commonly occur in estuaries. They are truly euryhaline and can live in fresh water for extended periods. Moonyfishes are predators and feed primarily on smaller fish and invertebrates. They are found primarily in shallow water and form large

shoals In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. I ...

. Two extinct species, ''

Psettopsis ''Psettopsis subarcuatus'' is an extinct, prehistoric moonyfish that lived during the Lutetian epoch of Monte Bolca, Italy. It had large, rounded dorsal and anal fins, and was a comparatively large fish, being about 45 centimeters long, much la ...

subarcuatus'' and ''

Pasaichthys ''Pasaichthys pleuronectiformis'' is an extinct, prehistoric moonyfish that lived during the Lutetian epoch of Monte Bolca, Italy. The average length of its fossils is about 6 centimeters. In life, it would probably resemble its living relativ ...

pleuronectiformis'', are known as fossils from the

Lutetian The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the ...

lagerstatten of Monte Bolca,

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

, in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

In aquaria

Aquarists Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. There is also a piscicultural fishkeeping industry, serving as a branch of agriculture. Origins of fishkeeping Fish have ...

commonly keep ''M. argenteus'' and ''M. sebae'' as pets in domestic aquaria, where they are known as monos or Malayan angels; they are also widely kept in

public aquaria A public aquarium (plural: ''public aquaria'' or ''public Water Zoo'') is the aquatic counterpart of a zoo, which houses living aquatic animal and plant specimens for public viewing. Most public aquariums feature tanks larger than those kept b ...

. They are hardy and easy to care for, but require

brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

and copious swimming space

External links

* {{Taxonbar, from=Q588431 Monodactylidae, Perciformes families Taxa named by David Starr Jordan Taxa named by Barton Warren Evermann Extant Eocene first appearances