Ornamental freshwater fish types are classified by hobbyists and aquarists into many different groups as per taxonomy, feeding habits, their preferred niche in the water, temperature tolerance and community living.
The freshwater aquarium fish types available today are from various parts of the world. They have their own food habits, climatic preferences and compatibility.
Taxonomic classification of freshwater aquarium fish types
In taxonomic classification freshwater fish types suitable for aquarium rearing come from myriad of families, genera and species. Almost any aquatic animal can be kept in an aquarium as in the case of public aquaria displaying even big sharks.
However for home aquarium, freshwater fish types are narrowed down to some main groups and a brief description of the suitable families is given below.
Most of these fish types belong to the group cyprinodonts (tooted carps). As the name denotes these types of fish give birth to young fish babies differing with most of the other fish which lay eggs. Among these guppies, mollies, swordtails and platies are the most common types for freshwater aquarium.
All the other common freshwater aquarium fish types come under the category of egg-layers. Goldfish, betta, gourami, tetra etc.. come under this group.
Siamese fighter (betta) and gourami are the most popular in this group. These have labyrinth organ which allows them to take oxygen directly form the air. Most of them show parental care of eggs and babies.
Carp family consists of very popular freshwater aquarium types like goldfish, fantail, oranda, moor, ranchu, pearl scale, koi, danios, barbs etc.
Many high value species like angelfish, oscar, discus come under this group and these have originated from Africa and America. Many are carnivorous in nature and some are omnivores.
Tetras, hatchetfish, pencilfish, silver dollar, headstander come under this group. Most of the characins are schooling fish. They comprise carnivores, herbivores and omnivores.
These are also called armoured catfish and are suitable for freshwater community tanks. Corys accept all types of food. A number of varieties are there suitable for beginners as they are peaceful, hardy, small, active and easy to keep.
They are also called dragonfish and are aggressive in nature. There are a number of varieties with varying colours. In young stages they school in groups.
They suck in air into their swim-bladder and can breathe it.
In bigger sizes they are preferably kept alone as they may attack the weaker ones including their own species.
Loaches belong to the family of catfishes are bottom living scavengers. They are very docile, shy, active and are very easy to keep. Clown loaches, kuhli loaches, zebra loaches, yoyo loaches and dwarf loaches are some of the varieties. They accept all types of food.
Apart from loaches there are number of attractive catfish for freshwater aquarium. They are scaleless and some can breathe air directly. They are hardy, bottom living scavengers cleaning the bottom of the freshwater aquarium.
Classification of freshwater aquarium fish types as per their feeding habits
Freshwater aquarium fish are also grouped as per their feed preferences. In nature the alimentary canal varies as per the feeding habits. Carnivorous varieties have short alimentary canal whereas the herbivorous and algal eaters have long one.
Some of them have no preferences and take all types of feed and are called omnivores. However most of them can be trained to take formula feed in the freshwater aquarium.
Arowanas, many cichlids and betta come under the carnivores whereas many herbivores are among the carp family.
Grouping of the freshwater aquarium fish types as per their temperament
Depending upon compatibility fish can be divided into aggressive (arowana, betta, flowerhorn), semi-aggressive (angelfish), peaceful (guppies, loaches), community loving (mollies, guppies, platies,goldfish) and schooling Aquarium fish types(cardinal tetras, neon tetras, pencilfish).
Grouping of freshwater aquarium fish types as per their temperature tolerance
Tropical freshwater aquarium fish types can stand fairly warm waters and can live comfortably at even at 80 degrees F. Some examples are betta, guppies, arowana and gourami. They require heating to maintain temperature of the tank in the cold climates.
Cold freshwater aquarium varieties can thrive well below 20 degree F and do not require heating normally. Goldfish and koi are some of the examples.
Freshwater aquarium fish can also be classified into different types like bottom-living, column-living, surface-feeding, requiring open space and those freshwater aquarium fish types requiring hiding places.