Diamond tetra care guide
Also called: Diamond characin, Pittier's tetra
The diamond tetra is a peaceful, 2.4 in (6 cm) shoaling fish from Venezuela whose scales sparkle like glitter once it matures. Keep six or more in a planted 20 gallon (76 L) tank with soft, slightly acidic water.
Diamond tetras need a tank of at least 20 gallons (76 L), a group of 6 or more, and water at 24–28°C (75–82°F) with a pH of 6–7. They grow to about 6 cm (2.4 in) and are peaceful.
Plan a tank with diamond tetrasSee all tank mates
Diamond tetra quick facts
| Scientific name | Makunaima pittieri |
|---|---|
| Family | Acestrorhamphidae |
| Origin | Lake Valencia basin, Venezuela (most in the trade are farm-bred) |
| Adult size | 6 cm (2.4 in) |
| Minimum tank | 20 gallons (76 L), at least 75 cm (30 in) long |
| Temperature | 24–28°C (75–82°F) |
| pH | 6–7 |
| Hardness (GH) | 5–12 dGH |
| Group size | 6 or more (shoaling fish) |
| Temperament | Peaceful |
| Swims at | Middle |
| Diet | Omnivore |
| Care level | Easy |
| Lifespan | 3–6 years |
| Safe with shrimp? | Mostly (eats baby shrimp) |
| Safe with plants? | Yes |
Tank setup
Give a group of six at least a 20 gallon (76 L) tank about 30 in (75 cm) long. Plant the back and sides and leave open water in front for swimming. A dark substrate and soft light make the shimmer stand out. Moderate filter flow is fine; they do not need a strong current.
How many diamond tetras in a tank?
The smallest common tank that suits diamond tetras is a 20 gallon long. Here is roughly how many fit in each size when they are the only fish, based on adult size and waste output. Leave room if you want tank mates.
| Tank | Diamond tetras (alone) |
|---|---|
| 3 gallon | Too small |
| 5 gallon | Too small |
| 10 gallon | Too small |
| 15 gallon | Too small |
| 20 gallon | Too small |
| 20 gallon long | 6–13 |
| 29 gallon | 6–19 |
| 40 gallon | 6–26 |
| 55 gallon | 6–37 |
| 75 gallon | 6–50 |
| 125 gallon | 6–84 |
What you need for diamond tetras
Sized for a 20 gallon long tank, the smallest common size that suits a group of 6 diamond tetras. For a different tank or a mix of fish, use the stocking calculator for a list sized to your plan.
Tank and equipment
- 20 gallon long aquarium (tank or kit) (opens Amazon in a new tab)Bigger tanks are more stable and easier for beginners. How to choose
- Aquarium stand for 20 gallons (opens Amazon in a new tab)The water alone weighs about 167 lb (76 kg), before glass, gravel and rock. How to choose
- Adjustable heater, 75 W (opens Amazon in a new tab)Holds about 79 °F (26 °C) in a room at 65 °F (18 °C). How to choose
- Aquarium thermometer (opens Amazon in a new tab)Check it daily: heaters can fail stuck on or off. How to choose
- Hang-on-back filter rated 80–120 GPH (opens Amazon in a new tab)Community tank: 4–6 times the tank volume per hour. How to choose
- About 45 lb of aquarium gravel (opens Amazon in a new tab)Enough for a layer about 2 in (5 cm) deep. Smooth gravel suits most community fish. How to choose
- Water conditioner (dechlorinator) (opens Amazon in a new tab)Removes chlorine and chloramine from tap water. Seachem Prime is a popular, concentrated choice. How to choose
- Liquid test kit (ammonia, nitrite, nitrate, pH) (opens Amazon in a new tab)Liquid kits are more accurate than strips. The API Freshwater Master Test Kit is the common choice. How to choose
- Gravel vacuum (siphon) (opens Amazon in a new tab)Cleans the gravel and does the water change in one go. How to choose
- LED aquarium light, about 30 in long (opens Amazon in a new tab)Match the light to the tank length. Basic LEDs grow easy plants. How to choose
Food and extras for diamond tetras
- Tropical fish pellets (opens Amazon in a new tab)A good staple for medium community fish.
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Water parameters
Aim for 24–28 °C (75–82 °F), pH 6.0–7.0 and soft to medium water around 5–12 dGH. Farm-bred fish cope with slightly harder, alkaline water, but they color up best when it is a little acidic. Change part of the water every week to keep nitrate low.
Best tank mates for diamond tetras
These popular species share diamond tetras' water needs and temperament. See the full list of 76 good matches.
Cherry shrimp
3 cm (1.2 in) · 20–27°C (68–81°F)
Nerite snail
2.5 cm (1 in) · 22–27°C (72–81°F)
Bristlenose pleco
12 cm (4.7 in) · 22–26°C (72–79°F)
Bronze corydoras
7 cm (2.8 in) · 21–26°C (70–79°F)
Assassin snail
2.5 cm (1 in) · 22–27°C (72–81°F)
Ramshorn snail
2 cm (0.8 in) · 21–27°C (70–81°F)
African dwarf frog
3.5 cm (1.4 in) · 22–26°C (72–79°F)
Amano shrimp
4.5 cm (1.8 in) · 20–27°C (68–81°F)
Avoid keeping diamond tetras with
- Common goldfish: They need different temperatures: Diamond tetra 24–28°C (75–82°F), common goldfish 15–22°C (59–72°F).
- Fancy goldfish: They need different temperatures: Diamond tetra 24–28°C (75–82°F), fancy goldfish 18–23°C (64–73°F).
- Oscar: Oscar can eat diamond tetras: they're small enough to fit in its mouth once it's grown.
- Chinese algae eater: Chinese algae eater is aggressive and will bully or injure peaceful diamond tetras.
- Convict cichlid: Convict cichlid is aggressive and will bully or injure peaceful diamond tetras.
- Dojo loach: They need different temperatures: Diamond tetra 24–28°C (75–82°F), dojo loach 18–23°C (64–73°F).
Feeding
In the wild it eats small insects, worms and crustaceans. In the aquarium it takes flakes and small granules without fuss. Add frozen or live bloodworm, daphnia and brine shrimp a few times a week, plus a vegetable flake now and then. It will also eat any baby shrimp it finds.
Behavior
A calm community fish that cruises the middle of the tank. In groups smaller than six it gets nervous and may nip fins, so keep a proper shoal. Good companions are other mid-sized tetras, rasboras, corydoras, small plecos and dwarf cichlids. Avoid slow, long-finned fish and anything big enough to swallow it.
Breeding
Males grow larger, with longer, flowing dorsal and anal fins and more sparkle. Spawn a conditioned pair or small group in a dim tank with soft, acidic water and spawning mops or mesh on the bottom. Remove the adults once eggs appear, because they eat them. Fry swim after a few days and need infusoria, then baby brine shrimp.
Tips from experienced keepers
- Young diamond tetras look plain in the shop. The full sparkle takes several months to develop, so be patient.
- A shoal of eight or more is calmer and much less likely to nip fins.
- Floating plants and a dark background make the scales shine.
- Do not keep them with bettas or other slow, long-finned fish.
Frequently asked questions
How many diamond tetras should be kept together?
Keep at least six, and eight or more if your tank allows. A bigger group is calmer, more colorful and less likely to nip fins.
How big do diamond tetras get?
Adults reach about 2.4 in (6 cm). Males usually end up a little larger than females and have longer fins.
Are diamond tetras fin nippers?
They can nip when kept in small groups or when stressed. In a proper shoal they are peaceful, but it is still safest to avoid long-finned tank mates such as bettas.
Sources
We checked these references when writing this page. Values are for healthy long-term keeping, not survival limits. Last reviewed 2026-10-13. See our editorial policy.