Diamond Tetra Care Guide

Tank Size for Diamond Tetras

Diamond Tetra Care Guide7 mins read

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Diamond tetra care guide
The Diamond Tetra is a popular and striking Freshwater aquarium fish that is easy for beginners to keep and an attractive variety for aquarists. Image from Flickr

The diamond tetra is a popular and striking Freshwater aquarium fish that is easy for beginners to keep and an attractive variety for aquarists. They bring about a certain charm to any aquarium, and there are some variants too – notably the diamond neon tetra. Furthermore, because of their friendly and peaceful nature, they are perfect to keep with other peaceful fish species.

If you love shiny iridescent fish with mesmerizing colors, you will love the Diamond Tetra. That said, read on to find out a bit more about the species, diamond tetra size and tank setup, and how to create the perfect environment to care for it.

Breed Overview

OriginLakes and Streams in South America
Lifespan3 – 5 Years
Size5 – 7cm (2 – 3 inches)
ColorsBlack, Blue, and Blue Neon
Tank Size20 – 30 Gallons, the minimum for six fish is 15 Gallons
TemperamentPeaceful, Shoaling, Social, Active
Water TypeClean Freshwater
Water Temperature24–28°C (75–82°F)
Water pH0 – 7.0
Difficulty LevelBeginner Friendly and Easy to Keep and breed

Species Summary

The Diamond Tetra, scientifically known as the “Moenkhausia pittieri, or Monk Tetra are peaceful, small freshwater fish. It is native to the rivers and lakes of South America, especially Lake Valencia, and Venezuela.

They are called Diamond Tetra because of the lustrous, iridescent appeal of their scales when they become mature. In fact, these resemble glistening diamonds. The species is from the Characin family with clear differences between adult males and females, which we will look further into.

Color Variations Of The Diamond Tetra

Color variations of the diamond tetra
Essentially the Diamond Tetra fish is Silver with semi-transparent fins that have a hint of violet in them. Image from Flickr

Did you know that the Diamond-like appearance of the diamond tetra is because the scales refract light in such a manner that it reflects different colors and shimmers?

Essentially, the Diamond Tetra fish is Silver with semi-transparent fins with a hint of violet. When mature the scales become more iridescent. On top of this, the colors will change depending on the angles that they are viewed.

The scales can have several different colors such as green, blue, orange, gold, and silver. Similarly, the eye colors of the Diamond Tetra are striking and different, the upper portion of the eye has a subtle red dash. The diamond neon tetra is a variant that has a neon stripe, which makes them very striking.

Male And Female Sexual Dimorphism

You will notice that female Diamond Tetras have a much shorter dorsal fin with a round shape. On the other hand, males have a pointed dorsal fin that is longer. Males tend to be more streamlined and slenderer, while females are larger and bulkier than males. Luckily both males and females boast striking glistening scales. However, the females are slightly duller, although in the diamond neon tetra they are still very interesting looking.

Other Colors

Other notable color variations in the Diamond Tetra include:

  • The Black Diamond Tetra – This is the fish you may also hear called the ‘diamond neon tetra’.A variation of the neon Tetra with shiny black scales, though not related to the Original Diamond Tetra.
  • The Blue Diamond Tetra – Not to be confused with the Diamond Head Neon Tetra, it is ideally a Blue color variation of the Diamond Tetra.
  • The Blue Diamond Neon Tetra – The blue diamond neon tetra is a variation of the Neon Blue Tetra that does not have the blue neon stripe, but rather blue shimmering scales on its head, and it’s smaller in size.
  • The Long Fin Diamond Tetra – Mostly Male Diamond Tetras may be referred to as Long Fin Diamond Tetras because of their longer dorsal fins.

Diamond Tetra Size And Lifespan

Diamond tetra size and lifespan
Diamond Tetras when mature can reach sizes of between 4.5 – 7cm (2 – 3 inches), and females are larger than males. Image from Flickr

You may have noted that the diamond tetra is slightly more bulky than other Tetra species, and larger. In fact, diamond tetra size is one factor that attracts aquarists to them. Diamond Tetras when mature can reach sizes of between 4.5 – 7cm (2 – 3 inches), and females are larger than males.

They have a lifespan of between 3-5 years. Though they are a smaller species of fish, you need to keep in mind that they need a group of six or more fish, mixed with males and females.

Temperament And Behaviour Of Diamond Tetras

Most Tetra species, in general, are very peaceful shoaling fish that can be playful with each other, and that are quite active. When they feel stressed or threatened in any way they may nip at other longer-finned fish. Additionally, like other Tetra species, they do not get along with Betta fish species.

Diamond Tetras need companions that are the same species. Otherwise, they can quickly become stressed, and slightly nippy towards other fish. Due to diamond tetra size this can be quite damaging to smaller tank mates! They generally enjoy the company of their species much more and tolerate other tank mates. However you can keep the diamond tetra and the diamond neon tetra together with no problem.

General Care

As the diamond tetra is such a resilient and friendly fish, they are easy to care for. They’re also not hard to match up with the right companions for a communal tank.

Tank Set-Up

Tank set-up for diamond tetra
Diamond Tetra enjoys soft and slightly acidic water that is clean and clear, with a pH of between 6.0 and 7.0.

Before we get started with creating an aquarium for your Diamond Tetra, it is always crucial to consider their origin. Diamond Tetras have a natural habitat of very clean, and slow-moving streams and lakes. These have much vegetation to make them feel safe. Thus, ideally, you should mimic this, to keep them happy and healthy.

  • Tank Size – Because you need to keep a group of at least 6 fish a larger tank of around a minimum of 15 gallons, or 20 – 30 gallons is required.
  • Water Conditions – Diamond Tetra enjoys soft and slightly acidic water that is clean and clear, with a pH of between 6.0 and 7.0.
  • Water Temperatures – They are tropical fish, thriving in warmer water conditions and tropical areas. Thus, temperatures of between 24–28°C (75–82°F) will be ideal.
  • Filter – They prefer very clean water. Therefore, it’s best to use a strong filter with an adjustable slow current. Mostly Hang on Back Filters are your best option.
  • Heater – Unless you live in a very warm area where the temperatures do not drop too low, you will need a heater. This should be around 150 watts per 30-gallon tank.
  • Other Equipment – As you will see when it comes to cleaning and maintenance it is always a good idea to have a siphoning hose. You can use this alongside a tank vacuum or cleaning pad for the sides as another option. A pH testing kit and thermometer are a necessity though.
  • Light – Diamond Tetras, like other Tetra species, prefer dimed light conditions, and need absolute darkness at night. A low light is ideal with enough plants and dark substrate to give a more darkened environment for them.

Tank Décor

Diamond Tetras enjoy a lushly planted tank with a dark sand or gravel substrate. They also like plenty of hiding spaces. To create a more natural feel, driftwood, rocks, and caves can be used as décor. For Tetras it is better to use live rather than synthetic plants such as long-stemmed rooted plants, and floating plants.

Amazon Swords, Java Moss, Java Ferns. Hygrophila, Polysperma, Water Wisteria, Duckweed, Amazon Frogbit, water Sprites, and Guppy Grass are all excellent choices. A plus point with Live plants is that they will oxygenate and clean your tank water. Some species may even serve as a tasty snack for your Diamond Tetras, and other community fish.

Introducing Your New Fish

Introducing your new fish to diamond tetra
You can keep them with other Tetra species, Dwarf, and smaller peaceful Gouramis, Rasboras as well as bottom feeders such as Loaches and Corydoras. Image from Flickr

When you are sure that your tank is set up to your liking, ensure your test kit and thermometer readings are all in check. Now, after cycling the tank, you are now ready to add your fish.

Choosing A Healthy Fish

Choose a healthy group of diamond tetra fish from a reputable breeder or pet store. Ensure that the fish is active and swimming, with clear skin and bright eyes. Take note of any damage to the fins and body. This can look like patches, white spots, or a swollen belly that may indicate health issues. With the diamond neon tetra, the stripe should be bright and they should have lustrous colors.

Adding Fish To The Tank

You can follow these steps to properly acclimate your fish before placing them in their new home:

  • Let the bag with the fish float on the tank surface for around 20 minutes, to acclimate your fish.
  • Replace the water in the bag with that of the tank, a cup at a time. This will take around three to four cups at 10 to 15-minute intervals.
  • Release your fish into the tank. Do not allow too much of the water from the bag into the tank, however, This is to prevent the ammonia from entering your tank.

Selecting Tank Mates / Companions

Should you wish to keep other fish species with your diamond tetra shoal, or to have happy and calm Diamond Tetras, there are some things to consider. To begin with, professional aquarists recommend you have a school of at least 6 fish, so account for diamond tetra size when thinking about how much room your shoal will take up. Ideally, there will be more if you can, consisting of both males and females.

In a well-planted tank where they are happy and schooling with their kind, you will have no issues. The diamond tetra will easily get along with other peaceful fish that are smaller or similar in size.

You can keep them with other Tetra species, Dwarf, and smaller peaceful Gouramis, Rasboras as well as bottom feeders such as Loaches and Corydoras.

Some other species to consider are:

  • White Cloud Minnows
  • Cherry Barbs
  • Zebra Fish
  • Nerite Snails
  • Celestial Danios
  • Small crabs
  • Shrimps

Then again, if you are adding more fish of other species to your tank, you may need to strongly consider a larger tank. This is to accommodate all your fish and to prevent overcrowding, which could cause stress and aggression.


Diamond tetras are omnivores
Diamond Tetras are Omnivores requiring a diet with plant and protein-based foods. Image from Flickr

The diamond tetra is an Omnivore, requiring a diet with plant and protein-based foods. In-home aquariums they will eat mostly quality flakes and pellets as a staple food. However you can give them vegetables, and meat-based foods, as a single meal, or treat.

  • Live and Frozen Foods – Brine Shrimp, Daphnia, Mosquito Larvae, Blood Worms, and aquatic larvae.
  • Plant Material – Blanched and finely chopped Zucchini, Carrots, Lettuce, Spinach, and Kale.

How To Feed Your Diamond Tetras

Feed your diamond tetra fish twice a day in the morning and evening preferably. One meal should be a snack such as meat-based or vegetable-based food. The other should be fish flakes or pellets. Feed enough for them to finish within a few minutes.

Tank Maintenance

In order to keep your diamond tetra fish healthy and stress-free, they need very clean and clear water parameters.

You will need to do a weekly water change of at least 25% of the tank water, with new fresh conditioned water. Keep the side of the inside and outside of the tank clean, and remove all old food and dead plant matter. You may need to clean décor and synthetic plants occasionally. Likewise, you can use a vacuum to clean the gravel in your tank.

Common Pests And Diseases

Common pests and diseases in diamond tetra
Most of the time pests and diseases are brought into a clean tank with the addition of a new fish or plant that may be carrying it, unknowingly. Image from Flickr

The diamond tetra is one of the species that is very resilient and will rarely get ill. However, this is only given that they have a suitable and clean environment, with healthy tank mates and vegetation.

Most of the time pests and diseases are brought into a clean tank with the addition of a new fish or plant. Whilst you do not intend harm, these may be carrying it, unknowingly. In other cases, incorrect water parameters and dirty water are your culprits for pests and diseases.

Common health issues found in Diamond Tetras:

  • Flukes – Trematoda Flukes are small worms that may irritate the skin and gills of your diamond tetra fish. They are tiny and cannot be seen with the naked eye, though you may notice redness and irritation on the skin of your fish, and your fish constantly rubbing itself against objects. Most over-the-counter parasitic worm treatments can be used, and you may have to quarantine sick fish.
  • Ichthyobodo – Also referred to as Ich, it is a Protozoan parasite that causes white spots on your fish. It is generally caused by infection, stress, and an unsanitary tank environment. Improving water conditions, quarantining your affected fish, and increasing aquarium salts are your best options for a cure. This may take a week or so.
  • General Bacterial Infections – Bacterial Infections can cause issues such as Fin Rot, where the fin and skin become infected, Dropsy, where the swim bladder is infected, or an eye infection. Most bacterial infections are treated with an antibiotic from a veterinarian. You should likewise move your fish to a quarantine tank with optimal water conditions that are slightly warmer.

How To Breed Your Fish

How to breed your diamond tetra fish
A single Diamond Tetra female can lay between 350 – 600 eggs of which at least half will be fertilized. Image from Flickr

The diamond tetra is an egg scatterer that provides no parental care. Nevertheless, they are easy to breed, and all you need is a separate tank. They have a reputation as prolific breeders because of the large number of eggs that they lay. A single Diamond Tetra female can lay between 350 – 600 eggs of which at least half will be fertilized.

  • Breeding Tank – Create a separate tank of around 20 to 30 gallons with plenty of plants. These should have fine leaves, and provide good shading. Adjust the water temperatures to slightly higher, around two or three degrees. Lastly, ensure that the water is clear with good parameters.
  • Spawning – Tetras prefer one female per male. You can also keep them in male and female groups to spawn if you need. However, like with general tank setup, account for diamond tetra size if you do this and realise you may need a larger breeding tank. They will spawn early in the morning laying eggs all over, while the male fertilizes them.
  • Egg and Fry Care – After spawning you should remove the parents as they tend to eat their eggs. The fry should hatch within 24 to 36 hours. Then, it will take around 2 to 3 days before they become independent in which case you can feed them baby brine infusoria. As the diamond tetra fry get older you may need to rehome them or move them to a larger tank.

One last note! Remember if you cross the diamond tetra with the diamond neon tetra, you can’t guarantee what the offspring will look like.

Final Thoughts

The Diamond Tetra
The Diamond Tetra species is one of the most spectacular of the Tetra species, with its lustrous colors that shimmer, and change as they swim actively. Image from Flickr

The diamond tetra species is one of the most spectacular of the Tetra species, with its lustrous colors that shimmer, and change as they swim actively. They are easy to care for and a joy to have in any communal tank, with the right water conditions. Whether the regular diamond tetra, or the diamond neon tetra, you will find one that is right for you.

If you wish to breed them, they are just as easy to breed, and you may soon have more tiny little ‘Diamonds’ swimming around than you can handle.

Frequently Asked Questions

What is the Smallest Tank Size for Diamond Tetras?
Diamond Tetras are active Shoaling fish that enjoy space to swim around, so I do not recommend a small tank. For a group of six, which is the minimum, Diamond Tetras, a 15-gallon tank, is the smallest that you can go.
What is the Difference between Male and Female Diamond Tetras?
Female Diamond Tetras are usually larger and bulkier than the streamlined males. Males have pointy and longer fins and slightly more vibrant colors. Though, it’s quite difficult to have sex with them when they are young. If you choose to breed it is important to select a male and female Tetra that is mature, and at least one year of age to be sure.
What Is Diamond Tetra Temperament Like?
The Diamond Tetra is very peaceful, social, and active, though when they get stressed because of poor water conditions, or being the only of their species, they can become anxious and aggressive. That is why we recommend that you get them in larger groups, as they thrive in the company of their species.
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Tal Halperin

Tal is an avid fish keeper and has been raising ornamental fish for decades. As a little boy, he drove his father crazy to buy him an aquarium with all the necessary equipment. Now, after a career in the field, he has set up Your Aquarium Place to offer the most comprehensive guide to ornamental fish keeping available and share his passion for the different species he has looked after.