Tankwise

A sparkling, deep-bodied tetra whose males' glittering scales and long fins reward a little extra care.

  • Temperature23–28 °C
  • pH6–7.5
  • Minimum tank70 L
  • DifficultyIntermediate
FoodFlake/pellet + frozen
Feeding1–2 feeds a day
Water change25% weekly

Behaviour and habits

The diamond tetra is a peaceful, deep-bodied shoaler whose scales glitter like diamonds in good condition, a shimmering effect that deepens with maturity and a varied diet. The males grow long, trailing fins, which makes the fish striking but also vulnerable to nipping tankmates. It schools loosely in mid-water and looks best in a planted tank with subdued light, where the glittering scales stand out.

What to feed, and how often

Flake, micro-pellet and frozen foods such as daphnia and bloodworm; feed one or two light meals a day. It is unfussy, and a varied diet and stable, soft-to-neutral water keep the glittering colour at its best.

Water changes and maintenance

Change about 25% weekly in soft-to-neutral water, matched closely. It is a touch more delicate than the hardiest tetras and rewards stability and a mature tank, disliking sudden swings.

Care and how easy it is

Keep it away from fin-nippers and in a settled tank; a group of six or more shows it at its best.

Common health problems

Prone to ich and fin rot, and its long fins are easily damaged by nippy tankmates.

If it gets sick

Avoid fin-nippers, keep the water clean and stable, and treat early if the fins are damaged.

Good tank mates

BettaBeginner with a prepared single-fish tank
BettaBetta splendens
  • 24-26 C
  • pH 6.5-7.5
  • 40 L+; 45 x 30 cm base
Bettas & gouramis | Territorial | Carnivore
GuppyBeginner with population planning
GuppyPoecilia reticulata
  • 22-26 C
  • pH 7.0-8.5
  • 60 L+; 60 x 30 cm base
Livebearers | Social; males pursue females | Omnivore
PlatyBeginner
PlatyXiphophorus maculatus
  • 20–26°C
  • pH 7–8.2
  • 50 L+
Livebearers · Peaceful · Omnivore
MollyBeginner
MollyPoecilia sphenops
  • 22–28°C
  • pH 7–8.5
  • 70 L+
Livebearers · Peaceful · Omnivore

Best avoided with

Similar species

Neon tetraIntermediate; stable group aquarium
Neon tetraParacheirodon innesi
  • 21-25 C
  • pH 6.0-7.5
  • 60 L+; 60 x 30 cm base
Tetras & rasboras | Peaceful shoaler | Omnivore
Cardinal tetraIntermediate
Cardinal tetraParacheirodon axelrodi
  • 23–28°C
  • pH 5–6.8
  • 60 L+
Tetras & rasboras · Peaceful · Omnivore
Black widow tetraBeginner
Black widow tetraGymnocorymbus ternetzi
  • 22–27°C
  • pH 6–7.5
  • 60 L+
Tetras & rasboras · Peaceful · Omnivore
Rummy-nose tetraIntermediate
Rummy-nose tetraHemigrammus rhodostomus
  • 24–28°C
  • pH 5.5–7
  • 60 L+
Tetras & rasboras · Peaceful · Omnivore

Compare at a glance

ParametersDiamond tetraNeon tetraCardinal tetraBlack widow tetra
Parameters
Temp23–28 °C20–26 °C23–28 °C22–27 °C
pH6–7.55.5–7.55–6.86–7.5
GH4–15 °dGH2–12 °dGH1–8 °dGH4–15 °dGH
Min. tank70 L50 L60 L60 L
Size6 cm3 cm4 cm5 cm
DietOmnivoreOmnivoreOmnivoreOmnivore
TemperamentPeacefulPeacefulPeacefulPeaceful
DifficultyIntermediateIntermediateIntermediateBeginner

Care guides

GuideHow Often Should You Feed Fish?Overfeeding causes more aquarium problems than underfeeding. Here is a realistic feeding routine, and the signs that you are giving too much.GuideHow Often Should You Change Aquarium Water?Water changes remove waste that the filter cannot, and keep minerals topped up. There is no single number, but there is a simple way to find yours.GuideHow to Treat Ich (White Spot Disease)Ich looks alarming but is one of the most treatable fish diseases. Act early, raise the heat, and it clears within a week or two — here is how.

New to the words? See the aquarium glossary.

Sources and research notes

Parameters are typical ranges for the species in home aquariums and vary with the individual fish and the water you use.