Should I buy it?
Pearl Danio
Danio albolineatus
A fast-moving 6 cm schooler with a pearl iridescence. Hardy and peaceful but needs open swim space and a long tank for natural behaviour.
Pearl Danio tank mates · 80L tank size hub
peaceful · beginner care
Sources & confidencehigh · partially verified · beginner: excellent
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: Community tanks 80L or more with a school of eight and horizontal space. Works in hard or soft water.
Avoid if: Your tank is short or a cube, or you keep very slow-moving or nano fish that get outcompeted for food.
Common mistakeHousing pearl danios in a nano cube is how keepers invent glass-to-glass pacing that stresses every quieter fish. They need horizontal swim length and a real school. A pretty cube is the wrong footprint for a danio built to cruise.
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: pearl danios are perfect nano-cube community fish for any small display. Reality: they are active schoolers that need length and six or more fish — in a short cube they pace endlessly and stress calmer tank mates without pause.
- 2.Buying three or four to start. Pearl Danio 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.Pearl danios jump readily. Any gap in the lid will be found within days. Hardier than they look, tolerating subtropical temperatures and settling fast in a community tank with brisk water movement.
About this species
Pearl danios are 6 cm Southeast Asian cyprinids with a pearlescent blue-pink sheen along the flanks. They hold a fast school in the top half of the tank and tolerate 18 °C, so they overlap with white cloud minnows. Active jumpers. Lids must be tight.
- Golden / Beckford's pencilfish80L min · same group, comparable tank size
- Tiger Barb80L min · same group, comparable tank size
- Black ruby barb100L min · same group, similar adult size
- Brown / hockey-stick pencilfish100L min · same group, similar adult size
- Cherry Barb60L min · same group, similar adult size
- Dwarf pencilfish60L min · same group, similar adult size
- Harlequin Rasbora60L min · same group, similar adult size
- Lambchop / Espei rasbora60L min · same group, similar adult size
- Amano Shrimpalso beginner peaceful, similar tank size
- Beckford Pencilfishalso beginner peaceful, similar tank size
- Black Neon Tetraalso beginner peaceful, similar tank size
- Black phantom tetraalso beginner peaceful, similar tank size
- Bloodfin tetraalso beginner peaceful, similar tank size
- Bristlenose Plecoalso beginner peaceful, similar tank size
- Hillstream Loach tank mateslists this fish as a safe and recommended mate
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 ease82
- Peacefulness90
- Community fit79
- Small-tank fit100
- Hardiness76
- Energy86
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 90L+ 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: Harlequin Rasbora, White Cloud Mountain Minnow, Zebra Danio.
Prioritise 6+ of Pearl Danio in 80L+ with filtration sized for messy feeding — add only mates that already pass pair checks with this species.
Compatibility
Tank mates for Pearl Danio
Usually safer (engine GOOD): Harlequin Rasbora, White Cloud Mountain Minnow, Zebra Danio. Conditional (CAUTION — read the pair page before buying): Angelfish, Corydoras Catfish. Avoid (RISKY): Discus, 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: Pearl Danio + Harlequin Rasbora
Behaviour and temperament
Pearl danios are peaceful but highly active schoolers. They stay calmer in six or more with real swim length. Stress shows as endless pacing and nervous neighbours when the tank is short or the school is too small to settle.
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 the upper midwater of a long tank with pearly flanks.
- High activity is normal — plan length and calm-enough neighbours.
- Glass pacing in a nano cube means footprint failed before food brand.
- A dull trio usually needs more of their own kind and more length.
- Low listed malice; stress to others comes from motion and crowding.
- They rarely start fin wars with robust similarly active fish.
- Move them to a longer tank before adding shy nano species.
- Grow the school only when swim length already exists.
Fish behaviour can vary between individuals and tank setups. Always observe new fish closely after introduction.
Water, food, and grouping
Hardness
medium
Diet
omnivore
Pearl danios are active surface-leaning omnivores that take flake, micro-pellets, and frozen foods in a school of six or more. Food monopolised in a corner leaves shy fish thin. Feed across the length of an 80L+ tank so the whole school reaches meals while they pace.
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 18 to 26 °C steadily on a real thermometer, not the dial on the heater.
- Aim for pH 6 to 8 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 80L published minimum for adults.
- You can stock at least 6 individuals (group welfare).
- Heater can hold 18–26°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 80L minimum tank needs a filter rated for at least 320L/hr turnover and a heater to hold 18–26°C reliably.
Plant suggestions
Pearl Danio does well in planted tanks. Plants compatible with 18–26°C and pH 6–8:
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. Danio albolineatus
Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).
- FishBase. Danio albolineatus
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Danio albolineatus
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 Pearl Danio
- How big do Pearl Danio get?
- Pearl Danio adults reach about 6 cm. Shop fish look smaller; stock for the adult length.
- What size tank does Pearl Danio need?
- 80L is the planning floor for adult swimming space and bioload. A 98L+ tank is the more comfortable long-term footprint. Length and depth matter as much as raw litres for active or territorial fish.
- Are Pearl Danio aggressive?
- Pearl danios are peaceful but highly active schoolers. They stay calmer in six or more with real swim length. Stress shows as endless pacing and nervous neighbours when the tank is short or the school is too small to settle.
- Do Pearl Danio 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 Pearl Danio?
- Housing pearl danios in a nano cube is how keepers invent glass-to-glass pacing that stresses every quieter fish. They need horizontal swim length and a real school. A pretty cube is the wrong footprint for a danio built to cruise.
- What fish can live with Pearl Danio?
- The Pearl Danio profile lists Harlequin Rasbora, White Cloud Mountain Minnow, Zebra Danio among its safer pairings (engine-checked GOOD). Angelfish, Corydoras Catfish are conditional (CAUTION): workable only with the specific conditions on each pair page. Avoid Discus, Oscar (RISKY). Run the pair checker for your exact water and tank size before stocking.