Introduction To The Fish Families

There are many families of freshwater fish living in the warmer parts of the world. Most of these have at least some species which are suitable for the aquarium.

Representatives from 21 families are described here, which have been chosen as being among the most suitable for aquarists.

Here, there should be something for everyone; bright, lively fish; quiet, secretive fish; large specimens and small specimens; delicate, showy varieties and hardy, ever-popular varieties.

The descriptions which follow are intended to give you a brief introduction to each family; the fish finally chosen for your aquarium, may well have characteristics which a general description cannot describe fully.

Anabantidae
Members of this family are also referred to as 'labyrinth' fish, due to an organ in their heads which enables them to breath air if necessary.

The family is native to the waters of Africa and Asia.
Members of the family originating from Asia have ventral fins modified for sensing food.

These 'feelers' protrude in front of the fish to detect food in the dark waters of their natural habitat.

Many members of this family produce characteristic floating bubble nests.

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Anostomidae
The Anostomidae are a family of South American fish, many of which adopt a 'head-down' position for swimming or resting.

This is thought to be a form of protective camouflage when among plants

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Callichthyidae
Catfish are a varied family of hardy, bottom-dwelling fish which can survive in near-stagnant water if necessary, since they have the ability to breath atmospheric air.

Some members of the family have strong suckered mouths, with which they can cling to stones, or graze algae from the aquarium tank walls.

Many of the most suitable tank specimens are members of the genus Corydoras, characterized by the possession of large, bony plates along the sides of the body.

Catfish have a wide distribution in North and South America, Europe, Asia and Africa. Various egg-laying methods are are adopted by the Callichthyidae.

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Centrarchidae
The Centrarchidae is a small family of North American fish, represented here by the species Elassoma evergladei.

The family is also known by the common name of sunfish.

Sunfish are able to tolerate much colder water conditions than most other species.

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Centropomidae
Members of this family are usually found in marine or brackish conditions, and those kept in aquaria, thrive best in water in which a tablespoon of salt has been added to each gallon of water.

Centropomids suitable for aquaria originate from Asia.

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Characidae
Members of this family comprise one of the largest freshwater fish families in the world.

This varied group ranges over Central and South America and most of Africa south of the Sahara, although the largest number of representatives come from South America.

The wide variety of species means that the aquarist is sure to find specimens suitable for all types of tank.

Characins are characterized by the possession of either teeth or an adipose fin, and sometimes both.

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Cichlidae
Cichlids are territorial, mainly carnivorous fish from Asia, Africa and Central & South America.

A high degree of parental protection, such as mouth-brooding, is exhibited by cichlids, which are considered to be among the more highly evolved of the fish species.

Despite the aggressive reputation of the family, many species make excellent aquarium inhabitants.

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Citharinidae
Most of the members of this African family are too large for the normal aquarium, but a few species are suitable.

The Citharinidae are closely related to the Characidae.

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Cobitidae
The Cobitidae, or loaches, are widely distributed over Europe, Asia and parts of Africa.

They are bottom-dwelling fish with flattened undersides, a mouth well served with sensory barbels (or feelers) and their bodies are often armed with erectile spines - such as those situated in front of the eyes - which act as a defense mechanism.

Loaches may take air from the surface, an indication that they have evolved to live in stagnant waters.

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Cyprinidae
The Cyprinidae consists of about 1,500 species scattered throughout most of the world, and include cold water types as well as those of tropical waters.

Cyprinids rely on teeth in their pharynx to break up their food.

Most have sensory barbs, indicating a food-probing way of life in the bottom layers of the water.

Included among the familiar cyprinid aquarium species are the barbs, rasboras, danios and minnows.

The Cyprinidae are egg scatterers, preferring to disperse their eggs throughout the tank, rather than relying on the burying or hanging methods favored by other families.

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Cyprinodontidae
This family comprises the egg-laying toothcarps or killifishes.

The egg-laying toothcarps, which are found in parts of North and South America,

Africa and Southern Europe and Asia, have mouths armed with teeth, which make them active predators of other, smaller species.

They prefer slightly acidic water and dimly lit conditions.

Two methods of egg laying are recognized:
The egg-hangers lay their eggs among the roots of floating plants, and the egg-buriers (as their name suggests) prefer to bury theirs in clumps of peat or other suitable substrate material.

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Gasteropelecidea
The hatchet fish are South American fish with characteristically shaped bodies resembling hatchets.

The large, upward inclined pectoral fins are used to assist gliding when the fish jump out of the water and 'fly' short distances - probably to escape danger.

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Gobiidae
The gobies are a large family of about 600 different species, ranging widely throughout the Caribbean and much if Asia.

Although shy at first, gobies soon settle down and are an undemanding fish, often showing interesting parental egg-guarding behavior.

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Hemiodontidae
The Hemiodontidae are small South American fish with slender bodies.

They are often known as pencil fish. They are related to characins, but possess teeth in the upper jaws only.

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Monodactylidae
Also known as pencil fish, the monodactylidae are found along the coasts and estuaries of of Africa, southern Asia and Australia.

They prefer to live in conditions suitable for brackish water species.

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Nandidae
Native to the waters of South America, India, Africa and parts of Asia, these are predatory, large mouthed fish with voracious appetites.

The majority spawn on the bottom of the tank, with the male guarding the young.

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Notopteridae
These are large fish with long bodies, known as knife fish.

The small scales and extended anal fin give these fish an unusual appearance.
Members of this family are found in both Africa and Asia.

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Poeciliidae
The Poeciliidae, or live-bearing tooth-carps, are a family of small fish originating from the southern part of North America, Central America and the northern part of South America.

The anal fin of the male forms a sexual organ known as a gonopodium, with which sperms are introduced into the female.

Live young are produced, which are capable of self-sufficient swimming and feeding minutes after they are born.

Included in this family are the guppies, platys, mollies and swordtails.

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Scatophagidae
Scats are a small family of fish found naturally in the river mouths, estuaries and coasts of south-east Asia and northern Australia.

They have deep, laterally compressed bodies, two dorsal fins, and feed by scavenging on plant and animal matter.

These are brackish water fish.

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Siluridae
The Siluridae are found throughout most of central and northern Europe, and much of Asia.

They are mostly bottom feeders with large sucker-like mouths.

Members of this diverse family are useful additions to the aquarium, since they are undemanding and hardy, as well as having a useful purpose by grazing algae and general tank debris.

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Toxotidae
The Toxotidae are also known as archer fish, due to their unique method of obtaining food by squirting jets of water at insects sitting on the overhanging foliage, to knock them into the water.

Archer fish are found in the coastal waters of India, Indonesia, Australia and the Persian Gulf.

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