What to Know About Diamond Tetra

Reviewed by Vanesa Farmer, DVM on December 10, 2022

The ornamental fish trade is a booming global industry that generates billions of dollars every year. Over 90% of this trade involves freshwater fish. One of the most popular freshwater groups is tetras. 

Diamond tetras in particular are a beautiful species within the tetra family. They’re very popular with aquarium owners and may at first seem like low-maintenance pets. But diamond tetras have unique needs that you should be aware of before bringing them home. With proper care and maintenance, diamond tetras are a bright, shiny addition to any freshwater aquarium.

All tetras are in the biological family Characidae. This family includes over 150 genera and hundreds to thousands of species. Lots of tetra species are popular in the aquarium industry, including the related species of neon tetras, black neon tetras, and black-skirted tetras. 

The scientific name for the diamond tetra fish is Moenkhausia pittieri. It also goes by several common names including the diamond characin and Pittier’s tetra. The diamond comparison is based on their bright, iridescent scales. Diamond tetra fish flash like jewels when they swim around your tank. 

These fish are widely available in pet stores and ornamental fish hatcheries. Both farmed and wild-caught fish are available for purchase. If you’ve decided on these fish for your aquarium, try looking online for the best place to acquire them in your area.

Diamond tetras are only found in one particular natural area — Lake Valencia in Venezuela. You can also find them in waterways that are connected to this lake.

This means that they’re one of many species that are specific to the South American branch of the ornamental fish trade. In general, South America is one of the most well-established and profitable regions for finding and distributing ornamental fish.

Unfortunately, human pollution has significantly affected natural populations of diamond tetra. They’re currently difficult to find within Lake Victoria and — at present — established populations are only easy to spot in nearby waterways. 

They prefer areas with a lot of leaf litter and other natural debris so they can hide.

Tetras are small, delightful fish that — in the wild — are always found in groups. The average diamond tetra size is quite small. Their maximum size is just over 2 inches long.

Both males and females have silver bodies and purple fins. The dorsal fins in the males tend to be much longer and more elaborate than those of the females. Males also tend to be slightly brighter and more colorful than females. 

Both sexes have red marks above their pupils and a dark band that runs along the midline of their bodies. 

The average diamond tetra lifespan in the wild isn’t clear. Relatives — specifically neon tetra — can live for up to a decade in the wild but don’t do as well in aquariums. These tetras only make it an average of five to eight years in aquarium setups. Several factors are to blame for this decreased lifespan. In general, the more thoroughly you take care of them, the longer they’ll live.

In nature, diamond tetras are omnivores. This means that they eat whatever they can scavenge from their environment — including both plant and animal life. But they prefer other animals and insects over plants. In the wild, they mostly feed on: 

In home aquariums, they do just fine on most brands of fish flakes and pellets. This is good for mixed community tanks because it can be hard to balance the dietary requirements of distinct ornamental species. Luckily, researchers have shown that tetra species thrive on commercial brands, particularly ones that are formulated for tetras. 

Pay attention to the protein and fat sources when you’re picking out your commercial brand. The best choice is a pellet that’s made from species that tetras encounter in the wild. 

You should feed them commercial products once or twice a day, depending on how many fish you have. You can also occasionally feed them treats like frozen bloodworms and live daphnia to vary their nutrient intake.

Never purchase a single diamond tetra for your aquarium. They are very social creatures and should only be kept in groups of five or more. Make sure you have the room and resources to take care of this little group. 

Diamond tetras are even content in community aquariums that involve multiple species. For example, they get along well with many species of danios, another popular kind of freshwater fish. 

In general, you should try to mimic the native environment of your fish as closely as possible. For diamond tetra, this includes: 

  • A slightly acidic water pH — ideally between 5.5 and 6.5 or 7
  • A tropical temperature range — ideal diamond tetra temperatures are between approximately 75 degrees Fahrenheit and 83 degrees Fahrenheit 
  • A minimum aquarium size of 20 gallons, especially if you’re keeping them in a mixed aquarium setup — for example, eight tetras and eight danios can happily live together in a 20-gallon environment 
  • Nitrate levels lower than 50 parts per million and nitrite levels lower than 10 parts per million
  • Fake or freshwater plants for shelter — you can also provide things like rocks to give your fish places to hide
  • A basalt substrate to coat the bottom of the tank
  • A high-quality filter
  • A light source — one experimental setup provided large overhead lights for 10 hours each day followed by 14 hours of darkness

You should perform regular water changes to help maintain these tank conditions. You can test some of the more specific parameters with commercial test strips.

Like all pets, diamond tetras can develop health issues. Sometimes you can modify their food or habitat and see positive improvements, however. 

For example, temperature and pH readings outside of the recommended ranges can significantly affect your fish’s health. If you start to notice any problems, you should thoroughly check all aspects of their environment for issues.  

Tetras also commonly develop a problem called endocardiosis — inflammation of the inner lining of their hearts. This problem is normally caused by an underlying infection. For example, they could become infected by bacterial contamination in your tank. Endocardiosis can lead to death. Make sure to keep your tank clean and free of bacterial and fungal growth to prevent health problems like this one. 

With proper care and maintenance, your diamond tetras will lead long, happy lives. They’re fantastic additions to most home aquariums.

Show Sources

Animal Diversity Web: “Characidaea Characins,” “Moenkhausia pittieri Diamond characin.” 
Animals: “Performance of Co-Housed Neon Tetras (Paracheirodon innesi) and Glowlight Rasboras (Trigonostigma hengeli) Fed Commercial Flakes and Lyophilized Natural Food.” 
Comparative Physiology and Biochemistry Part A, Molecular and Integrative Physiology: “Effects of temperature on food intake and the expression of appetite regulators in three Characidae fish: The black-skirted tetra (Gymnocorymbus ternetzi), neon tetra (Paracheirodon innesi) and Mexican cavefish (Astyanax mexicanus).”
Digitala Vetenskapliga Arkivet: “Explorative behavior of diamond tetra and their shoal formation in artificial environment: A comparison between farmed and wild-captured diamond tetra (English).” 
Encyclopedia of Life: “Diamond Tetra.” 
Fishbase: “Moenkhausia pittieri Eigenmann, 1920 Diamond tetra.”
Japanese Fighting Fish: “How Long Do Neon Tetras Live: Factors Swaying Their Lifespan.”  
Journal of Comparative Pathology: “Endocardiosis in Tetras (Family Characiformes).”

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