Diamond tetra care guide

The diamond tetra (Moenkhausia pittieri) belongs to Characidae family. The fish got its name due to its opalesque scales, that are especially beautiful at dim light. However, to see the full richness of the coloring you’ll have to wait, since the juveniles are quite plainly colored.

Habitat in the wild

Venezuela is a birthplace of the diamond fish or, more precisely – coastal area of Lake Valencia (Carabobo State), Aragua and Guacara rivers.

Valencia is located between two chains of mountains and it is the second largest lake in Venezuela. Water quality as a rule is very poor there mainly due to contamination as a result of human life and activities, agriculture and industrial production.

Thus, there is constant process of eutrophication there (this is the process of water quality degradation because of excessive ingress of so called ‘biogenic elements’ into the water, nitrogen and phosphorus compounds in the first place) and this causes algal bloom.

Studies showed that species diversity of the fish has reduced almost by 60% starting from the middle till the end of the 20th century. Diamond tetra inhabits in thickly planted areas of the lake and in several of its slow tributaries.

Scientific NameMoenkhausia pittieri
Common NamesDiamond tetra, diamond fish
Ease of keepingMedium
Lifespan5 years and more
Tank size200 liters (52 gallons) and more
Tank typeCommunity of fishes
Temperature72-78 °F (22-26 °C)
Water hardness9–20 dGH
Sizeup to 2.4 inches (6 cm)


In the wild diamond tetra grows up to 2.4 inches (6 cm) long, in a tank it is 4,5-5 cm (2 inches) long. The lifespan is about 5 years.

Its flat body is covered with silvery-gray scales, each of which shimmers like a diamond in reflected light. The pectoral fins are transparent, colorless, the rest of them have violet-blue tint.

Females are a bit smaller than males, they are less brightly colored and they don’t have that many scales on their body. Their dorsal is rounded and the rest of their fins are shorter, than those of the male. Females have not very pronounced greenish-gray lateral stripe that starts from the tail fin base and goes along the body. This stripe is almost absent on the male body. The fatty fin is pale pink.

Top of the diamond tetra iris is red. The scales on the whole body shimmer, that’s why the fish is called diamond tetra. However, only reproductive species can demonstrate this fascinating coloring, because the juveniles are rather pale colored.

Difficulties in keeping

It is quite easy to keep the diamond tetra, especially if you have some experience in aquarium husbandry. Since the fish is a renown one, it is massively bred, which means that it is adapted to local conditions.

However, still it is desirable to keep the fish in soft water.

Care and keeping in a tank

Tank size

Diamond tetra is a schooling fish that is rather suitable to keep in a spacious community tank with thickly planted perimeter, floating plants, dim lighting and dark colored bottom substrate. Recommended number of the species is 6, because this way you will have a chance to see all the beauty in a school in a tank with opaque lighting.

In a community of 10-15 relatives the behavior becomes even more interesting: the males show themselves in front of the females, they unfold their tail fins and their scales shimmer. The body and fins coloring gets darker and the scales have bronze tint.

During their mating games they very often spawn, but it is almost impossible to save the eggs in the community tank. Therefore, such large school requires a roomy tank (from 200 liters, 44 gallons capacity).

Tank decor

This fish can also be kept in a tank with Amazon biotope, though diamond tetra doesn’t dwell in Amazon river. Combination of dim light and black water in such biotope make the coloring look as gorgeous as possible. Use river sand as the bottom substrate and add some branchy snags. Several handfuls of dry leaves (beech or oak tree ones) will complete the simulation of the natural biotope look.

Water parameters

Tank water parameters have a wide range of acceptable values. The fish requires soft, slightly acidic and very clean water. A powerful filter with filtering medium that acidifies water will help you with this task.

The diamond tetra feels comfortable at 22-26 °C, pH 6-7.5, provided with weekly water renew (10-15% of the total tank volume).


In the wild diamond tetra feeds on small insects and spineless species living in water or fallen into it. This fish is easy to feed. It is an omnivorous one, it eats all types of live, frozen or artificial food. You can use flakes as the basic diet and feed it additionally with live or frozen food – bloodworm, brine shrimp.

This tetra can also damage tank plants, so it’s recommended to provide it with vegetable supplements to the diet. For example, spinach leaves or flakes containing plant components.

Tank mates

Diamond tetra is a good choice of fish for a community tank. It is quite appealing and peaceful fish, the males grow to be quite large. Diamond tetra is a good tank mate for most all of live-bearing species (platy, molly, swordtail), zebrafish, Odessa barb, rosy barb, congo tetra, tiger barbs and so on.

Are diamond tetras aggressive or fin nippers? Though the fish has a reputation of the one that nips fins, such behavior can be corrected as a rule by keeping the fish in a school of at least 6-8 species. When you keep this number of species in a group, any fights they have happen inside the group without hurting any other fishes in the tank.

This fish like almost all tetra species feels more comfortable together with other fishes of its kind and usually they are quite timid if there are not many of them in a tank.

Gender differences: male vs female

The diamond tetra male is usually larger, brighter colored and thinner, than the females. They also have nice large abdominal, dorsal and anal fins when they become reproductive. Males have more saturated violet tint, while it is barely seen on the females body.


To get the offspring put a couple of diamond tetra species into a separate volume of 10-15 liters capacity.

Water in the spawning tank should be soft and acidic in the range of pH 5,5-6,5, GH 1-5. It is recommended to maintain the water temperature at about 26-27 °C during the spawning. It is desirable to put the breeders separately for 6-8 days before spawning and feed them high with crustaceans and other live food kinds.

To prevent eating the eggs by the fish cover the spawning tank bottom with a net. You may also use bunches of small leaved tank plants for this purpose. The tank lighting should be dim and scattered. It is good to use natural subdued light from the window in this case.

It is better to put the diamond tetra in the spawning tank in the evening. If the fish are ready to spawn, they will start laying eggs the very next morning. Sometimes the spawning is delayed for 2-3 and more seldom for 5 days and the female hides from the male among the tank plants.

As a rule this delay is due to the fact that the eggs inside the female’s abdomen aren’t ready yet. In this case to trigger the spawning process you should add 1,0-1,5 liters of fresh soft water with temperature T= 29-30 °C. During the spawning male haunts the female actively and makes her lay eggs. This takes about 1,5-2 hours, sometimes more.

It depends on how ready the diamond tetra are for spawning and their physical condition. Usually the female lays 350-400 eggs from which only less than 40-60% are fertilized during the first spawning.

After the spawning is over, remove the breeders from the tank as well as the tank plants and the net (after removing the eggs from them). To prevent bacterial and fungi infection add some methylene-blue into the tank water.

Shadow the tank, but continue aerating the water. Or you can do it another way: renew 60-70% of the tank water with the fresh one of the same composition and temperature. This will also increase the amount of healthy and properly developing eggs in the tank.

The transparent diamond tetra larvae appears from the eggs approximately in a day at water temperature T= 26-27 °C. They lay on the tank bottom or stick to the volume walls.

On the 6th day the juveniles start to swim. They are large, dark colored with cross hatching and enduring. Feeding them is easy: give the juveniles infusorian during the first two days. Provided with such feeding the offspring grows by leaps and bounds.

A week later you can feed them with crustacean larvae, artificial micro food and chopped tubifex. Provided with high and proper feeding juveniles become 1 cm long on the 20th day of their life, but at that they still swim very little.

At the age of 1 month the juveniles get the shape and the coloring of their parents. Now this is the time to put them into a nursery tank.

Shortly before this, start gradually increasing the water hardness (this is necessary for the juveniles to develop properly) and make other water parameters of the spawning and nursery tank equal, by adding 1-2 glasses of water from the tank where the breeders live every day.

It is convenient to combine this process with feeding, by mixing filtered off plankton and water from the tank in a glass and then pouring the mixture into the spawning tank. By the age of 6-7 month old the young diamond tetra fish has all the distinctive features of adult species down to the gender dimorphism and they are ready to breed themselves.