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Passport
- Family
- Tetras
- Grows to
- 6 cm (2.4")
- Lives
- 3–6 years
- Temperament
- Peaceful
- Care
- Beginner
- Swims
- Mid-water
- Keep
- In a group of 6 or more
- Water
- 24–28 °C (75–82 °F)
Venezuela
Care requirements
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On record for Diamond Tetra: adult size, lifespan, minimum tank, temperature, ph, hardness, minimum group, diet, care level, swim level, tank length.
A figure that is not on record is left out rather than guessed. One marked Suggested comes from keeping knowledge rather than a page.
- Minimum tank 70 L / 18.5 US gal
- pH 5.5–7
- Hardness 5–12 dGH
- Diet omnivore
- Tank length 60 cm minimum
Care notes written from general aquarium knowledge, not from the cited sources.
About
Diamond tetras are the definition of a fish you buy on faith. Juveniles in a shop tank are a drab silver-grey with nothing to recommend them, and the adult male is covered in scales that scatter light into gold, green and violet as he moves, with long trailing fins washed purple.
Give them the better part of a year. That's roughly how long the change takes, and it's the single most common reason people pass them over — the fish for sale is not the fish you'll end up with.
They come from Lake Valencia in Venezuela, a lake so degraded by pollution and algal blooms that species diversity there collapsed through the last century. Almost everything in the trade is farm-bred now, which is just as well.
Tank setup
Plant your diamonds densely and keep the light down. They sulk in bright, bare tanks and the reflective scales that make the species need something to reflect other than a white lamp.
Give the males room to display at each other. That's where the fins and the colour come from, and a cramped tank produces a duller fish as surely as a bad diet does.
A dark substrate is close to mandatory. So is some floating cover, which breaks the light and settles them.
Wood, roots and leaf litter suit them and tint the water. They're adaptable enough for an ordinary planted tank, but the colours deepen below neutral.
Feeding
Diamonds are easy to feed and will take anything offered without hesitation. Flake and granules cover the basics perfectly well.
Condition is what earns the colour, though, and that means regular live and frozen food. Bloodworm, daphnia and brine shrimp a few times a week make a visible difference to both the sheen and the fin growth in maturing males.
They're greedy enough to outcompete shyer tank mates, so watch the quiet ones at feeding time.
Avoid: underfeeding a growing group. Males that don't get the protein never develop the fins.
Filtration and flow
Moderate flow suits them. Diamonds come from shallow vegetated lake margins and slow tributaries rather than fast water, but they're robust and handle a normal community filter without trouble.
Keep the tank well maintained. Their reputation for being hardy comes from farm breeding, not from any special tolerance, and long-finned males show poor water quality in their fin edges first.
Softer water below neutral gets the best colour, and harder water is survivable rather than ideal.
With plants
Diamond tetras are safe with plants and look better among them than in any other arrangement. They don't dig or graze.
Plant thickly at the back and sides and keep an open display area in the middle, because that's where the males will perform. A tank designed around that gets you far more to watch.
Floating plants earn their place here more than most tanks — the shade is what brings these fish forward.
Health
They're hardy and there's nothing specific to watch for. Ordinary community problems turn up and clear up.
Nipping is the behavioural issue rather than the medical one. Kept in too small a group diamonds get skittish and start on other fish's fins; kept in a proper shoal the squabbling stays inside the group where it belongs.
Long male fins are vulnerable to damage from decor and from other nippers, so keep them away from barbs and serpaes.
Breeding
Diamonds spawn much like other tetras and are not difficult once the adults are in condition. They scatter adhesive eggs among fine-leaved plants and then eat them.
Condition the group on live food, move a good male and a full female to a dim tank floored with mesh or thick with moss, and use soft acidic water. Take the adults out once eggs appear.
The eggs and fry are light sensitive, so keep the tank shaded. The fry start on infusoria and move onto baby brine shrimp within a week or so.
Tank mates
Avoid10
- Convict Cichlid Convict Cichlid grows to 15 cm against Diamond Tetra at 6 cm, big enough to eat it.
- Jewel Cichlid Jewel Cichlid grows to 15 cm against Diamond Tetra at 6 cm, big enough to eat it.
- Least Killifish Diamond Tetra grows to 6 cm against Least Killifish at 2 cm, big enough to eat it.
- Scarlet Badis Diamond Tetra grows to 6 cm against Scarlet Badis at 2 cm, big enough to eat it.
- Common Goldfish Common Goldfish is not safe with Diamond Tetra: common goldfish and tetras are a bad pairing.
Only with care11
- Chinese Algae Eater Chinese Algae Eater is aggressive and Diamond Tetra is peaceful.
- Cherry Barb Diamond Tetra and Cherry Barb are an uneasy mix: barbs and tetras are a pairing to watch.
- Gold Barb Diamond Tetra and Gold Barb are an uneasy mix: barbs and tetras are a pairing to watch.
- Odessa Barb Diamond Tetra and Odessa Barb are an uneasy mix: barbs and tetras are a pairing to watch.
- Paradise Fish Paradise Fish is a risk to Diamond Tetra: large gouramis and tetras are a pairing to watch.
No conflict is recorded with the other 85 species in the database, so nothing to flag. 2 species are not covered at all, so they could not be judged either way.