Diamond Tetra Expert Care Guide & Tank Set Up For Beginners

When young, Diamond tetras can often be overlooked due to their mundane appearance. But, provided with the right care, as they mature, Diamond tetras become sparkling and bright.

And if you’re a fan of iridescent and shiny things, then Diamond Tetras are the fish for you. With their mesmerizing appearance and relative ease of care, they’ve grown in popularity and have become a much-coveted show-stopping aquarium fish. 

This guide will tell you what need to know for these fish to live their best lives, such as their aquarium layout, diet, water conditions, tank mates, and more.

Overview & Origin: Diamond Tetra

Scientifically known as M. pittieri, Diamond Tetras have many other names, including Brillantsalmler, Timanttitetra, Pittier’s Tetra, and Diamond Characin. The name “Diamond Tetra” was given to this fish as it perfectly describes how its scales bend and refract the light just like a diamond does.

These scales have an iridescent, prism-like effect, mostly appearing to have a silver sheen that sparkles and shifts in color as the fish moves. These accents of color can be orange, gold, green, or bluish-violet.

Close up of Diamond tetra (M. pittieri) swimming in aquarium

The Tetra’s fins are translucent with a violet undertone. Even their eyes are colored, displaying a pop of red in the upper part. 

They’re larger than most other Tetras, having an average size of 2.5 inches. However, they still have the same flat, laterally-compressed body shape as well as the long dorsal and anal fins characteristic of Tetras. 

In nature, they are inhabitants of the Amazonian biotope. They’re found in shallow, slow-moving waters that are typically warm and of a pH that’s close to neutral. There, the Diamond Tetras go around in schools, constantly exploring and looking for their next meal. These waters tend to have lots of plants and are strewn with loads of fallen tree leaves. 

They originated in Venezuela, mainly occurring in the waters of Lake Valencia, as well as the Rio Bue and Rio Tiquiritu rivers. Over the years, they’ve started to disappear from Lake Valencia due to the pollution caused by human activities in this area. 

Fortunately, these fish are bred in various places and are still available in most pet stores for a moderate price.

Care Stats Overview

  • Tank size: 15 gallons
  • Temperature: 72 – 82 °F (22.2 – 27.8 °C)
  • pH: 6 – 7.5
  • KH: 4 – 8
  • Living zone: Middle and upper tank levels
  • Temperament: Peaceful
  • Diet: Omnivore

Scientific Classifications

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Characiformes
  • Family: Characidae
  • Genus: Moenkhausia
  • Species: M. pittieri


Most Diamond Tetras can live anywhere from 3 to 6 years. Their lifespan mostly depends on each fish’s genetics, but you can help them along by providing them with a good home.

A good diet, in addition to a stress-free environment and optimal water conditions, can do wonders. In the presence of those three things, Diamond Tetras can thrive and stave off any illness that can shorten their lifetime. 

Diamond Tetra Sexual Dimorphism: Size & Coloration

For this species, the only clear-cut sign to discern between the males and females is the dorsal fin length. Males tend to have much longer ones that curve and come to a pointed end. 

Other signs that may be less obvious to the eye are their body shape and color. Females are a bit bigger and rounder than their male counterparts. They also tend to be less vibrant and colorful. However, these two features are more difficult to notice and can be a bit unreliable.

Diamond Tetra Care & Tank Set-Up

Diamond tetra (M. pittieri) swimming in aquarium

Tank Size & How Many Can Be Kept Together

Diamond Tetras are schooling fish, meaning they need company to survive. Weirdly enough, they prefer to live in odd-numbered groups. So three Tetras should be the absolute minimum, but five or seven are generally better and give the fish a greater sense of comfort.

Therefore, you need to have a tank large enough to allow for a small group of Diamond Tetras. A 15-gallon tank is a good starting place for a three-membered group. 

For bigger groups, 20 and 30-gallon tanks are better because they’re easier to maintain in the long run. They also provide more than enough swimming space for the energetic Tetras.

The Nitrogen Cycle

Over time, organic materials such as leftover food, fish waste, and dead organisms will start to decompose and produce toxic substances, the most important of which is ammonia. For ammonia to be eliminated from the water, it has to be broken down into the less toxic substance nitrite, which is further broken down into the relatively safe nitrate. 

This degradation process is known as the nitrogen cycle and is present in every tank containing living creatures. To keep your tank’s water clean, you need to establish a bacterial colony, also known as cycling the tank. 

You also need to partially change the tank’s water regularly to get rid of any remaining toxins. With Diamond Tetras, you should replace from a quarter to a half of your water on a bi-weekly basis.

If you’re still a novice and can’t fully understand the implications of the nitrogen cycle and how to cycle your tank the right way, then make sure to check out this article. It’ll tell you all you need to know about this subject and will serve as a great refresher for any experienced aquarist.

Water Parameters

  • Temperature: Since Diamond Tetras come from the warm water of South America, it would be best if your temperature is in the 72 – 82 °F (22.2 – 27.8 °C) range. Ideally, stay in the middle of this range, at 76 °F.
  • pH: Diamond Tetras are a hardy species that can withstand a wide range of pH, stretching from 5.5 to 7.5. However, try to keep your tank’s water ever slightly so acidic as this will allow your Tetra’s beauty to come forth and shine. 
  • KH: Keep your carbonate hardness and alkalinity in the 4 – 8 range.
  • Hardness: Very soft to moderately hard waters are all okay with Diamonds Tetras. Therefore, your tank’s general hardness could range from 2 – 15 degrees.

Tank Set-Up

An environment that’s almost identical to the Tetra’s natural habitat allows them to be at ease. Since they come from densely vegetated streams and lakes, it’s imperative for your tank to be chock-full of plants. This is to ensure that the Tetras can hide at a moment’s notice.

Diamond Tetras can feel very exposed if they’re not surrounded by plants and other hiding spaces. If they can’t find a place to hide, they become very stressed and can even fall ill as a consequence.

So, make sure your aquarium has plenty of freshwater plants to make these Tetras feel safe and comfortable. It would be best to have a mix of rooted and floating, as well as tall and short plants.

These plants also provide the added benefit of shading the tank. Diamond Tetras are not huge fans of strong lights and prefer subdued lighting. The plants act as a barrier and filter the light passing through, creating a dimly lit backdrop.

See: Best LED Lights For Planted Aquariums

If you’re worried about not being able to see the Tetra’s iridescence, have no fear. The faint light will, in fact, bring out this effect to its limit and help your Tetras develop their best colors.

You can add some driftwood, tree branches, and dried leaves to the tank. They’ll provide more hiding spaces, give your tank a more natural feel, and color the water due to their tannin content. Just don’t forget to replace the leaves every few weeks.

As for the substrate, anything will do. Diamond Tetras spend most of their time in the middle and upper tank levels and rarely venture to the bottom. You can place sand, gravel, or a mixture of both according to your preference.

Last but not least, set your water flow to moderate strength. Any filtration system will do the trick as long as it’s in good shape.

Diet & Feeding

Feeding Diamond Tetras is a piece of cake. Since they’re omnivores, they can eat anything, including plants, living organisms, and quality fish food. In their native home, they survive on the surrounding vegetation and have a taste for insect larvae and worms due to their high protein content.

In your aquarium, dry food is more than enough to keep them going. Go for high-quality types that are rich in nutrients and vitamins. Flakes or pellets are both okay to use. 

Supplement their diet with live, frozen, or freeze-dried food. Daphnia, bloodworms, brine shrimp, and worms are some of the things they like to eat.

Also, make sure to include some blanched vegetables here and there to prevent the Tetras from nibbling on your tank’s plants. Spinach, zucchini, and especially lettuce are well-liked by Diamond Tetras. 

Also, remember to switch up their diet every now and then and feed them several times a day. Remove any leftovers after 3 minutes to preserve your water quality.

Behavior & Tank Mate Compatibility

Diamond Tetra are very peaceful fish that like hanging out with their kind and mind their own business. They can have some rough-and-tumble fights here and there, but they don’t intentionally cause harm. You’ll mostly see them going around in groups, exploring the tank, and looking for food.

They make for a great community fish, as long as they’re housed with other similarly sized, peaceful tank mates. Aggressive, semi-aggressive, and bigger-sized species should never be in the same tank as Diamond Tetras. They’ll either see the Tetras as food or possible threats.

Also, avoid species that are slow swimmers and eaters like the Bubble Eye and Celestial Goldfish. Diamond Tetras will outswim them and eat their food, leaving them to starve unless you carefully monitor their feeding sessions. 

Some fish that work well with these Tetras are Danios, Mollies, Rasboras, Guppies, and other Tetras. Peaceful bottom dwellers, like the Cory Catfish and the Otocinclus, are also suitable tank mates.

Breeding Diamond Tetras

Thankfully, breeding Diamond Tetras isn’t too complex of a process. The only hiccup you’ll encounter is finding suitable pairs. These fish only mate with a fish that’s the same age and size as them. 

Once you figure out which male goes with which female, you’re all set. Feed them live, nutritious food for a week or so, then transfer the pair into a separate 20-gallon tank. 

The new tank should be filled with slightly acidic and soft water, with a temperature of 79 – 84 °F. It should also contain spawning mops or Java Fern to catch the eggs. The lights should initially be turned off and gradually increased to induce the breeding process.

Once they’re ready, the male will chase the female for 1-2 days until she lays her eggs. He’ll then fertilize them, at which point you have to take out the adults, or else they’ll eat these eggs.

The eggs will hatch after a day or so, and they’ll feed on their yolk sacs for a few days. Once they start swimming on their own, they can be fed fry food. 

In the beginning, the baby Tetras don’t have the distinctive coloration of Diamond Tetras. They develop their final colors in 9 months or so, looking just as beautiful as their parents.

If you want to breed more than one pair in a tank, your only option is to get a group of six pairs. Diamond Tetras won’t pair in smaller or larger groups, so take care.

Will You Pick Diamond Tetras For Your Tank?

Diamond Tetras are one-of-a-kind species that will definitely be the crown jewel of your tank. They are something of a cheat card; they look like a creature that exists in a fairy tale yet are both so affordable and easy to take care of. These fish will give you no trouble as long as you provide them with what they need.

We hope we’ve covered everything you may need to know about this dazzling fish and wish you a successful journey with your Diamond Tetras.

Christopher Adams
Christopher Adams

Hey there, my name is Christopher, and I've successfully ran freshwater aquariums for the past few decades. The mission of this site is to make it simple for anyone to run their own freshwater aquarium.

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