Should I buy it?
Diamond Tetra
Moenkhausia pittieri
A tetra whose scales develop genuine iridescent sparkle at 12+ months. Easy to keep, underrated, and understocked in most shops.
Diamond Tetra tank mates · 120L tank size hub
peaceful · intermediate care
Sources & confidencehigh · partially verified · beginner: caution
Checked against several solid care sources that mostly agree. Numbers here are a careful starting point. Your tap water, tank size, and habits decide the rest. How we evaluate.
Best for: Planted community tanks 120L or more with a school of six at neutral pH. Patient keepers willing to wait for adult colouring.
Avoid if: You want immediate colour impact or keep highly acidic soft water.
Common mistakeJudging diamond tetras at purchase age is how keepers invent disappointment and impulse returns. Juveniles look plain silver; full diamond scaling takes eight to twelve months with good food and a real school. Buy for the adult look on a timeline, not for the bag photo on day one.
Top things that go wrong
- Group welfare — not a solo display fish. Plan at least **6** together for normal behaviour; smaller groups often mean stress, colour loss, or nipping depending on species.
- Shrimp & snails. Cherry shrimp and other dwarfs can coexist with peaceful small fish; baby shrimp are food for almost anything that finds them.
What most shops don't tell you
- 1.Myth: diamond tetras should sparkle like the adult photos the week you buy them. Reality: juveniles stay plain silver for months — full diamond scaling needs time, protein-rich feeding, and a settled school of six or more in softish water.
- 2.Buying three or four to start. Diamond Tetra settles in a group of 6 or more. An understocked school sulks at the back of the tank and loses colour within a fortnight.
- 3.Juveniles look plain and silver in a shop tank. The diamond scale flash only develops once the fish reach adult size in mature stable water, six to eight months in. The shop fish never matches the photo on the card.
About this species
Diamonds are deep-bodied South American tetras whose scales flash silver and violet under good aquarium light. The school is mid-water and active. The diamond sheen stays dull in sterile or chemically unstable water.
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- Penguin tetra80L min · same group, similar adult size
- Rosy Tetra80L min · same group, similar adult size
- Rummy Nose Tetra80L min · same group, similar adult size
- Splash tetra80L min · same group, similar adult size
- Beckford Pencilfish60L min · same group, similar adult size
- Adolfoi coryalso intermediate peaceful, similar tank size
- African freshwater butterflyfishalso intermediate peaceful, similar tank size
- Bamboo Shrimpalso intermediate peaceful, similar tank size
- Black ruby barbalso intermediate peaceful, similar tank size
- Boesemani Rainbowfishalso intermediate peaceful, similar tank size
- Bolivian Ramalso intermediate peaceful, similar tank size
No reverse lookups listed yet.
Plan grid
Key limits are above. Here: pH band, swim level, bioload, and activity.
Swim zones
Care snapshot
Quick compare before you buy. Not a score of how “good” the fish is.
- Beginner ease32
- Peacefulness90
- Community fit79
- Small-tank fit100
- Hardiness54
- Energy54
Numbers are deterministic planning indices from Fishori fields — not a scientific score of your individual fish.
Example setups
Starting points only. Run the pair checker for every fish you add.
Rough 120L+ layout: one calm centrepiece, 8–12 small tetras/rasboras, 6–8 corydoras-type bottom fish — verify every name in the pair checker before buying.
Safer directions include: Bolivian Ram, Honey Gourami, Neon Tetra.
Prioritise 6+ of Diamond Tetra in 120L+ with filtration sized for messy feeding — add only mates that already pass pair checks with this species.
Compatibility
Tank mates for Diamond Tetra
Usually safer (engine GOOD): Bolivian Ram, Honey Gourami, Neon Tetra. Conditional (CAUTION — read the pair page before buying): Corydoras Catfish, Tiger Barb. Avoid (RISKY): Jack Dempsey, Oscar. Every name links to a live pair check — the lists are a shortlist, not a stocking plan.
Usually safer
Open a pair page with this fish as the starting point.
Needs planning
Read the blocking rule on each pair page before experimenting.
Usually avoid
Do-not-stock combinations on conservative hobby rules.
Compare with
Run a real pair check: Diamond Tetra + Bolivian Ram
- Try Bolivian Ram — open the pair check.
- Try Honey Gourami — open the pair check.
- Try Neon Tetra — open the pair check.
Behaviour and temperament
Diamond tetras are peaceful midwater schoolers that stay calmer in groups of six or more. They do not police the tank. Stress shows as hiding and washed-out silver when the school is too small or the tank is short on midwater cover.
What sets them off
- Sudden crowding
- Poor water quality
Fin nipping: Not a habitual fin-nipper; stressed or crowded individuals can still test fins.
Predation: Not a predator toward similarly sized community fish; fry and dwarf shrimp are still fair game for most species.
Territory: Not strongly territorial, but still needs room so its working space does not overlap the next fish.
Planted tanks: excellent — easy plant ideas
In the glass: typical and warning signs
- Six or more cruise midwater; diamond sparkle builds slowly with age and food.
- Mild school shuffling is normal — not a cue to add boisterous barbs for ‘energy.’
- A thin, pale trio usually needs more of their own kind before a different staple food.
- Hiding after tiger barbs are added means neighbour choice failed.
- Low listed risk as aggressors toward similar-sized peaceful fish.
- They lose to nippy barbs long before they start community wars.
- Grow the school before chasing mystery colour fixes.
- Remove nippy neighbours at the first torn fin — planting will not reform the mix.
Fish behaviour can vary between individuals and tank setups. Always observe new fish closely after introduction.
Water, food, and grouping
Hardness
soft
Diet
omnivore
Diamond tetras are midwater omnivores that need months of steady nutrition before the diamond scaling finishes. Micro-pellets, flake, and frozen foods keep condition while juveniles still look plain silver. Feed a school of six or more in at least 120L so competition does not leave the shy end thin while you wait for adult sparkle.
Shrimp & snails
Cherry shrimp and other dwarfs can coexist with peaceful small fish; baby shrimp are food for almost anything that finds them.
Schooling species — buy 6+ together. Smaller groups stress and lose colour.
- Hold 22 to 28 °C steadily on a real thermometer, not the dial on the heater.
- Aim for pH 6 to 7.5 and a hardness you can re-test in two weeks. A one-time strip in the shop car park is not a water test.
- Schooling species. Buy 6 or more from the same tank on the same day before adding any centrepiece fish.
- Tank volume meets or exceeds 120L published minimum for adults.
- You can stock at least 6 individuals (group welfare).
- Heater can hold 22–28°C without cooking cooler-water tank mates.
Explore and stocking hubs
Tank-mates hub, matching guides, category peers, and litre stocking lists around this species’ minimum tank.
Plan with tools
Check mates as pairs first, then add this fish in the tank builder for the full stocking.
Filtration & heating
A 120L minimum tank needs a filter rated for at least 480L/hr turnover and a heater to hold 22–28°C reliably.
Plant suggestions
Diamond Tetra does well in planted tanks. Plants compatible with 22–28°C and pH 6–7.5:
Research: partially verified · Confidence: high · 3 linked source(s). We do not invent citations.
How Fishori evaluates compatibility (same logic as pair and tank tools).
- Seriously Fish. Moenkhausia pittieri
Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).
- FishBase. Moenkhausia pittieri
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Moenkhausia pittieri
Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.
Evidence notes
- The Seriously Fish profile for the binomial in this record was successfully reached as the primary aquarium reference.
- FishBase contributes natural-range size and habitat context. Translate those numbers through your heater, your water report, and your tank footprint before stocking.
- Wikipedia is only cited if the article URL returned OK. Use it for orientation, not as the only care sheet for an import.
- All compatibility text reflects typical hobby experience and the Fishori model. Individual fish, shop stress, and the order tank mates are added in can still defy a single-paragraph label.
Common questions about Diamond Tetra
- How big do Diamond Tetra get?
- Diamond Tetra adults reach about 6 cm. Shop fish look smaller; stock for the adult length.
- What size tank does Diamond Tetra need?
- 120L is the planning floor for adult swimming space and bioload. A 146L+ tank is the more comfortable long-term footprint. Length and depth matter as much as raw litres for active or territorial fish.
- Are Diamond Tetra aggressive?
- Diamond tetras are peaceful midwater schoolers that stay calmer in groups of six or more. They do not police the tank. Stress shows as hiding and washed-out silver when the school is too small or the tank is short on midwater cover.
- Do Diamond Tetra need to be kept in a group?
- Schooling species — buy 6+ together. Smaller groups stress and lose colour.
- What is the most common mistake with Diamond Tetra?
- Judging diamond tetras at purchase age is how keepers invent disappointment and impulse returns. Juveniles look plain silver; full diamond scaling takes eight to twelve months with good food and a real school. Buy for the adult look on a timeline, not for the bag photo on day one.
- What fish can live with Diamond Tetra?
- The Diamond Tetra profile lists Bolivian Ram, Honey Gourami, Neon Tetra among its safer pairings (engine-checked GOOD). Corydoras Catfish, Tiger Barb are conditional (CAUTION): workable only with the specific conditions on each pair page. Avoid Jack Dempsey, Oscar (RISKY). Run the pair checker for your exact water and tank size before stocking.