Tetra Fish: Characteristics, types, habitats , care and more

Tetra Fish is the common name for many small freshwater fish species widely used in aquariums. So if you want to have a really striking fishbowl don’t forget to read this article.

Tetra Fish General Characteristics

Before starting it’s important to clarify why the members of the Characidae family are called «Tetras».  The members of this family, in obsolete taxonomic classifications, were known as «Tetragonopteridae», whose abbreviation was obviously «Tetra».

Nowadays Tetra is limited exclusively to use in aquarism, name that will surely be perpetuated because of the universal and rooted of its use. Under this popular name are members of other families, such as Tetragonopteridae, Lebiasinidae, etc.

In the literature (books and magazines of Aquarium) they are also referred to as “characids” (which has nothing to do with the Genus Carassius, which belongs to the Ciprinidae family). Caracinids  is a synonym for “characids or Characidae.

The Tetra Fish General Traits

Most tetras fish display the following traits:

    • They are oviparous, free-spawners and don’t take care of their fry. (rather fry are swallowed without consideration).
    • Except for some particular species, they have a dorsal adipose fin near the caudal one.
    • Tetra fish have well developed teeth that vary according to the gender.
    • They are fast swimmers, very active and prefer grouping in schools by species.
    • Most have scales with metallic shine.
    • Colors are grouped in stripes, dots or spots. Very rarely they cover the whole body.
    • The shape of the body is not typical for the whole family, and varies significantly from one Gender to another.
    • Their behavior varies from absolutely peaceful to fiercely aggressive.

Tetra Fish: Feeding Habits

Most tetras fish are omnivores, meaning that they feed on both living animal and plant foods. Therefore they accept food in flakes, which must be varied and of good quality. Whenever possible they will be supplied with some live food, such as mosquito larvae, water fleas( Daphnia), well-purged and washed tubifex and eventually scraped raw meat, frozen and frozen beef heart with the vegetable grater or boiled chicken liver and stepped on.

Different Species of Tetra Fish

Let’s meet and learn about the whole family

Indian glassy fish, Indian glassy perch or Indian X-ray fish

Habitat and Distribution

Asia: Pakistan, India, Bangladesh, Myanmar, Thailand and Malaysia. There are also not totally confirmed sightings of Indian Glassy Fish in Nepal.


Indian Glassy Fish have a laterally compressed body and higher than long, which gives them a rhomboidal appearance. Their dorsal fin’s fore rays are hard while the posterior ones are soft.

Body’s Color

None, as their common name indicates. This is a fish whose transparency allows us to see without problems its skeleton and its internal organs. The young specimens, on the other hand, are more opaque and have several vertical black stripes along the body that disappear when reaching adulthood. Indian glassy fish are school fish that should be kept in groups of at least six individuals. They are often sold injected with fluorescent colors, like blue, yellow, green, purple among others.

tetra fish. Indian glassy fish


7-8 cm. In captivity Indian glassy fish rarely exceed 5 cm.

Sexual differences:

Males have a blue line on the edge of the dorsal and anal fins and have a less rounded swim bladder than females.

Indian Glassy Fish in Aquariums:

The aquarium for these fish must be of 40 liters at least. It’s also advisable to decorate it with many plants which will useful to maintain the water salinity as well as several rocks, trunks and roots so that they can take refuge.

Their tank-mates must be quite species that can stand brackish water such as wasp fish, molly fish, as well as other pecillidae that are adapted to live in this type of waters. The evaporated water must be replaced with distilled water, to avoid an increase in salinity.

Water parameters:

PH 6.5-7.8

GH 9-20 ° d.

Feeding Indian Glassy Fish:

You must alternate food in flakes with live food (brine shrimp, daphnia, small shrimp, mosquito larvae,) to avoid digestive disorders and provide them with the necessary nutrients.


Indian Glassy Fish are School fish, so they must be kept in groups of at least six individuals. They are sociable, quiet, shy and usually wander the middle zone of the aquarium (occasionally also the lower area).


Indian Glassy Fish are Oviparous. A 20 liters aquarium will be necessary to breed a male and a female with a temperature range between 24ºC and 28ºC and dim light (we can use floating plants to diminish the light intensity).

The females deposit around 100-150 eggs between the leaves of the plants and after carrying out the laying the parents must be removed. At that time, it is advisable to add 1 gr. of acriflavine per 100 liters of water to prevent fungi. The eggs hatch after 24 hours and the young must be fed with very small brine shrimp and/or nauplii.

let’s watch them

Lemon tetras (Hyphessobrycon pulchripinnis)

Lemon tetras have a wide and translucent yellow body. However, the most distinctive aspect of this species is given by the lemon yellow colored anterior thorny rays of the anal and dorsal fin that are somewhat elongated. Lemon tetras have also big eyes with and intense red coloration on the upper area as well as silver sides and an adipose fin. The males present a wide black border in the anal fin.


Up to 4 cm


Small streams of clear waters and dense vegetation from central Brazil.

Lemon tetras in aquariums

Lemon tetras are quiet fish very suitable for community tanks.  They enjoy swimming at medium depths requiring large spaces for such purpose. A Community aquarium with dim lighting and decorated with floating plants will be enough for this species. In addition frequent partial water changes are highly recommended for these tetras.

They get along very well with dwarf cichlids, catfish and other characins. However, the association with large cichlids that will end up altering the school due to territorial fights is not advisable.

Water conditions

PH 5.5 to 7.5;

Total hardness: up to 25º.

Soft to hard water

Temperature: From 23 to 26º C.


It’s very advisable to use a special tank for breeding lemon tetras. Moreover, keep in mind that the females must be fed with varied live food. This species does not reproduce as easily as most tetras.


LemonTetra Fish are omnivorous creatures that will accept small insects and larvae. They can also be fed with flakes and lyophilized food although live food is the most suitable option for them because of their nature.  An incorrect feeding of this species will lead to a significant loss in its coloration.

here they are

Emperor tetra (Nematobrycon palmeri )

Main Characteristics

This species of tetra fish has a laterally compressed body, with a long anal fin and caudal one divided into two. Emperor tetras lack adipose fins. From the operculum to the caudal fin the Emperor fish have a black band, and their fins are yellow, with some dark tones. They have a relatively high body and their most distinctive trait relies on the central spiny radii that males have in the caudal fin.  In addition, the Iris of the Emperor Tetra is of a bright green color.

This species of tetra fish has sexual dimorphism since, the male has dorsal and caudal fins more developed and pointed, and his body is slender and somewhat larger than that of the female. Moreover, the male has very elongated thorny radii on the center of the caudal fin. In contrast, the females of stubby bodies and more dull colors, don’t have both fins so developed.


The tetra emperor is a very peaceful fish that enjoys living in groups. However, it is not advisable to associate them with very lively species since they will feel uncomfortable.

Habitat and distribution

The tetra emperor is native to the northern areas of South America, (especially Colombia), and inhabits medium or deep waters in areas of heavy rainfall. This tetra is called the emperor because the dominant male of the group imposes itself on the rest as if it were a true emperor.

Feeding Emperor Tetras

The emperor tetra is an omnivorous fish that accepts very well the live food (daphnias, brine shrimp and cyclops), red meat and fish cut into small pieces and eaten in flakes. Emperor tetras also accept, small flaked and dried freeze drying, ,


The tetra emperors’ reproduction in captivity isn’t that easy to achieve and presents some difficulties. You must use a fish tank between 25 and 50 liters, with a temperature of 26 to 28 º C. You have to select the male well, because they are not all equal fecund. The chosen pair is placed in the aquarium in which should have peat and plants.

The spawn consists of a harassment of the male throughout the aquarium with continuous spasms that encourage the female to spawn. Eggs laying which is eggs by eggs and not very large occurs on the thin leaves of plants, usually in the morning. The parents eat the eggs so we must introduce some type of network or moss to avoid it. Once the laying is over, the parents must be removed.

The eggs will hatch after 24 or 32 hours. The larvae must be fed with plankton and then with newly hatched brine shrimp. Then you could use nauplii of brine shrimp or micro-worms. As they grow, their food is changed to tubifex. Properly fed emperor fish will reach maturity at half a year of age.

Emperor Tetras in Aquariums

The emperor Tetras are very suitable for community aquariums. They tend to prefer acid and soft waters like those of their natural habitats. It’s very recommended to keep them in groups of at least 6 specimens.

Floating plants and abundant vegetation are a must-have for these specimens, since they deposit the eggs among the plants. The water must be very soft and acid, with free spaces so that the emperor tetras can swim. Good filtration (with peat), low lighting and the preparation of a dark substrate Is recommended to enhance their colors.

    • Temperature: 24-28 º C
    • Ph: 6.5-7.5
    • Gh: 10 ° dGH

here they are

Boeseman’s rainbowfish  (Melanotaenia boesemani)

The rainbow fish is one of the most beautiful species among freshwater fish from around the world. It has several colors on its skin (hence its name) which capture with ease the attention of anyone. Its scientific name is Melanotaenia boesemani and it’s very suitable for aquariums since they provide a great ornamental contribution.


The Boeseman’s rainbowfish’s  body is flattened and shaped like an oval. They have a very structured physiognomy, since there is no differentiation between the dorsal and ventral areas. As time passes, their back presents a small bulge that allows us to estimate their age. The appearance of this sort of bundle is related to the specimens of advanced age.

It is also good to note that the anatomy of the tetra-rainbow fish has two dorsal and one anal fins. The anal fin is the continuation of their body.

It starts from the middle part and has a very important high-speed propelling function. With the dorsal fins he directs his movements. As for their mouth, it has a very peculiar feature: it is too narrow. Despite this, rainbow fishes have a voracious appetite. However, due to the inclination of their mouth, it is impossible for them to eat the foods that are on the substrate.


The rainbow fish have small proportions since their size ranges between 6 centimeters and 12 centimeters approximately. This characteristic makes it one of the favorite fish for ornamental breeding, as they do not acquire large volumes and can be kept in medium aquariums.

Distribution and habitat

These fish have a fairly limited distribution area, since there are few places where they live. They are usually found at the easternmost part of Southeast Asia in three locations: Indonesia, Australia and Nueva Guinea. The lakes where they can be found are the Ajamaru, Aintijo and Hain.

As for their habitat, they usually live in freshwater aquatic environments. Despite this, not all rivers are good habitats for these fish. They only live in certain rivers with specific characteristics. For example, one of the main needs for the river to be suitable is pH. So that they can harbor the rainbow fish, the water must remain with a pH range between 6 and 7.

The temperature is also a limitation. The ideal is about 15 ºC degrees. The more crystalline and clean the development, the more favorable it will be. This freshwater fish does not usually swim in depths because, as we mentioned before, it is not able to feed on the substrate foods because of the tilting of its mouth.

Another requirement that the habitat needs is that they have abundant aquatic plants and the temperature of the water is around 22-26 degrees. Sometimes, they can be kept at temperatures of 28ºC, although their development is not ideal.

Feeding Boeseman’s Rainbowfish

Rainbow tetra fish are omnivorous creatures. They can eat both small animals and aquatic plants. However, they need balanced nutrition and variety. If this is so, the brightness of their scales will be much stronger and the colors more showy.

For food in the aquarium, you have to select well the food that is going to be given. Their diet must be varied and it doesn’t matter if they are frozen or industrialized products. Both products provide and satisfy the needs of rainbow fish well. Even if you want, you can mix the food in the form of flakes or granules. You can also give them fish meat or small shrimp.

The frequency with which you should feed them is several times a day. The most recommended is three times. It is essential that food can remain suspended in the water, since they can’t eat food from the substrate due to the inclination of their mouth.

Therefore, any food that falls to the aquarium’s bottom will be unusable and the only thing that will do is to dirty the aquarium. To avoid these mishaps, rainbow fish must me provided with small amounts of food which will prevent them from descending to the bottom.

The issue of food can be a problem if we mix them with other fish. Although they are quite sociable fish, they are easily intimidated by the agility of other fish at mealtime. It is possible that they stay underground in the aquarium and don’t  go to the surface.

Necessary care

In order for the rainbow fish to feel at home, the aquarium must have enough space for them to swim. With about 200 liters they go well. The aquarium’s length must be at least one meter. The water has to be oxygenated with a good filter. The filter needs to provide movement to the water 3 or 4 times per hour. It is advisable to use a darker substrate so that the coloring of the fish is highlighted even more. We in vite you to read our article cardinal tetras to learn about other species of tetra fish

here they are

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