Pearl Danio Care Guide

The pearl danio is the zebra danio's bigger, plainer, prettier cousin — a fast, active shoaler of about 5.5 cm whose body throws an iridescent violet-to-pink sheen instead of bold stripes. Two facts govern the rest: it needs swimming length far more than gallons, and it is genuinely cool-tolerant, a fish for a long, room-temperature tank rather than a hot one.

Pearl Danio at a glance

The sourced figures the welfare engine uses to judge Pearl Danio — the parseable key facts.

Where it comes from

Danio albolineatus comes from across South-east Asia — Myanmar, Thailand, Laos, Cambodia, Vietnam, Peninsular Malaysia and Sumatra — and is a real generalist, found everywhere from well-oxygenated, clear hill streams with rocky beds running through forest to still ponds, ditches and rice paddies. That range writes the care sheet. The hill-stream and paddy generalist origin is why it is hardy and adaptable across a wide pH and hardness window and, crucially, cooler-tolerant than most tropical community fish; the well-oxygenated clear-stream half of its habitat is why it appreciates some current and clean water; and its surface-oriented, fast-water nature is why it is an accomplished jumper that demands a tight lid. Wild water runs about 16–25 °C, pH 6.0–8.0 and a very broad hardness band.

Did you know?

• Its trade name comes from an iridescent pearly violet-pink sheen — a structural shimmer that flares under actinic or moonlight, quite unlike its boldly-striped cousins.
• The species name albolineatus is Latin for 'white-lined', from albus ('white') and lineatus ('lined'), for the pale lateral stripe.
• It shares the genus Danio with the zebrafish (Danio rerio), one of the most important vertebrate model organisms in genetics and biomedical research, so it belongs to that same research-famous lineage.
• Older books and many shops still call it Brachydanio albolineatus — Brachydanio was the old small-danio genus later merged into Danio.
• The popular Gold Pearl Danio is not a wild morph but a semi-albino strain of the same species.
• With a wild range starting around 16 °C, it is one of the few 'tropical' community fish that genuinely thrives in an unheated, room-temperature tank.

Tank size — and why

Lead with swimming length, not volume — this is a fast, open-water cruiser, so the binding constraint is the base length of the tank. Seriously Fish sets the welfare target at a base of 90 × 30 cm, roughly a 30-gallon 'long', and that is what an active school really wants. A 20-gallon long of about 76 cm is a workable practical floor for a small group, but it is already shorter than that recommended 90 cm base, so treat it as the minimum rather than the ideal. Either way, prioritise a long, open mid-to-upper swimming lane over height; a tall tank wastes the dimension this fish actually uses, and a cramped, short one makes it skittish.

As a guide, a 20-gallon tank comfortably suits about 8 Pearl Danio as a single-species display, leaving room for tankmates.

How big does it really get?

Full-grown Pearl Danio reach about 5.5 cm (2.2 in) long, but they are usually sold at only about 2.5 cm (1 in) — a typical shop size (estimate). At full size, Pearl Danio needs roughly a 20-gallon tank, about 76 cm long; a common 10-gallon starter kit is only about 51 cm.

Adult size is sourced; the shop size is a typical-juvenile estimate; tank length is approximate for a standard 20-gallon aquarium.

Water parameters in practice

The temperature point is the one to get right: this is a cool-tolerant danio with a comfort band around 20–24 °C, tolerance down to roughly 16 °C, and a soft upper ceiling near 25 °C. It does not need a heater in a warm room and suits an unheated, sub-tropical community — but it is not a fish for a hot discus tank, and sustained warmth above about 25 °C brings on laboured breathing and reduced activity. Chemistry is wide and forgiving: pH 6.0–8.0 across a broad hardness range, which is part of why it is so beginner-friendly. Beyond that it is notably robust; the main avoidable stressors are chronic heat and the usual unstable, dirty water.

Diet & feeding

In the wild it is chiefly insectivorous, taking insects that fall onto the water plus some zooplankton. In the tank it is an unfussy omnivore that takes good-quality flake or a small pellet readily, varied with live or frozen bloodworm, daphnia, brine shrimp and mosquito larvae to bring up the iridescent colour and breeding condition. Feed small amounts once or twice a day. The behaviour at feeding time is the welfare-critical part: pearl danios are highly active, boisterous feeders that dart and even leap at surface food and will out-compete slow or timid tankmates — so make sure quieter fish actually get their share.

Gear & setup

Undemanding, with a couple of non-negotiables. A filter that delivers some current suits its clear-stream side; the fish likes well-oxygenated water and tolerates a brisker flow than most community tetras. No heater is needed in a warm room, and if used it should hold the cool side of the band. Any substrate works, though a darker one deepens the sheen, and rocky gravel nods to the biotope. Plant the edges and background but leave a long open swimming channel down the middle. The one mandatory item is a tight-fitting lid: pearl danios are accomplished jumpers that leap at surface food, so keep the top closed, especially right after feeding.

Temperament & behaviour

A very peaceful, obligate shoaling fish that spends the day cruising fast through the open mid-to-upper water and must be kept in numbers. It is not territorial and not a cross-species fin-nipper; the only intra-group behaviour of note is normal playful chasing, which rarely causes injury. Behaviour tracks numbers and space closely: a proper group in a long tank is bold, confident and colourful, while too few fish in too short a tank turn skittish and hover nervously in the upper corners, and the chasing gets over-directed.

Group & social needs

Keep a real group. The absolute floor is five or six, below which subordinate fish are stressed and a near-solitary fish becomes nervous, but Seriously Fish recommends at least eight to ten and that is the target to aim for. A larger school spreads the playful chasing, reduces skittishness and brings out the confident swimming and pearly colour the species is bought for.

Compatible tank mates (preview)

A short, engine-cleared shortlist — the species TankStocking's welfare engine clears with Pearl Danio and that suit its size and temperament best. Tap any to load the pairing in the planner.

• Amano Shrimp — Peaceful temperament, similar adult size.
• Bamboo Shrimp (Wood/Fan Shrimp) — Peaceful temperament, similar adult size.
• Black Neon Tetra — Peaceful temperament, similar adult size.

A note on the shrimp and snails here: Pearl Danio is peaceful and generally invertebrate-safe — but almost any fish will take very small shrimplets given the chance, so give shrimp dense cover (moss, leaf litter) if you want a colony to grow, rather than expecting every baby to survive.

This engine-cleared shortlist is Pearl Danio's tankmate surface for now — a dedicated tank-mates guide can follow for high-demand species.

Breeding & sexing

One of the classic beginner egg-scatterers, and easy. Sexing is moderately easy once mature: females are rounder-bellied, a little larger and slightly less colourful, while males are slimmer and more intensely coloured. Use a separate breeding tank with fine-leaved plants, a spawning mop, or a mesh or marble base to protect the eggs, and condition the group on live foods; like other egg-scatterers they spawn at first light. There is no parental care — the adults eat their own eggs, so remove them after spawning or rely on an egg-protecting base. Eggs hatch quickly, in about 24 to 36 hours; start the fry on infusoria and other very fine first foods, then move on to microworm and baby brine shrimp, and keep the water clean.

Lifespan

About five years in a well-maintained tank. What shortens it is unstable or dirty water and poor maintenance, chronic overheating above the recommended band — which brings laboured breathing and reduced activity — keeping too few fish so the shoal is chronically stressed, jumping out of an uncovered tank, and the friction of being kept with badly mismatched tankmates.

Common mistakes

• A tank that is too short. Buying for gallons or height instead of length leaves an active cruiser cramped — lead on footprint and aim for about 90 cm of base, treating a 20-gallon long as the floor, not the ideal.
• Too few fish. One to five turns into skittish fish hovering in the top corners; buy eight to ten or more.
• No lid. They are accomplished jumpers that leap at surface food and will end up on the floor — a tight cover is non-negotiable, especially after feeding.
• Mixing them with slow, timid or long-finned fish. Bettas, fancy guppies, slow gouramis and shy fish get out-competed at feeding and stressed by the constant fast motion.
• Keeping them too warm. This is a cool-tolerant fish; long-term temperatures above about 25 °C cause laboured breathing and shorten life, so do not house it with discus.

Signs of trouble

• A fish hovering nervously in the top corners, apart from the shoal — usually too small a group or too short a tank.
• A faded, dull sheen and clamped fins — general stress, often poor or unstable water, or being kept too warm.
• Laboured breathing and reduced activity — a classic sign the tank is running too hot for this cool-tolerant fish.
• Loss of appetite and isolation from the group — early stress or illness; check water quality and tankmates.

Is this fish right for you?

Do not buy pearl danios if you have a short or nano tank, cannot fit a school of eight to ten, cannot fit a tight lid, run a hot tank above about 25 °C, or have a community built around slow, timid or long-finned species such as bettas, fancy guppies and slow gouramis. On stock, note that the popular gold or yellow 'Gold Pearl Danio' is simply a semi-albino colour form of the same fish, not a different species; avoid dyed or painted stock as a welfare red flag, and pick active, full-finned specimens.

Common questions

What size tank do pearl danios need?

Lead with length, not gallons. The welfare target is a base of about 90 cm (roughly a 30-gallon long) for an active school; a 20-gallon long of about 76 cm is a workable floor but already shorter than ideal. They are fast cruisers that need a long, open swimming lane far more than height.

Do pearl danios need a heater?

Usually not in a warm room. They are genuinely cool-tolerant, comfortable around 20–24 °C with tolerance down to roughly 16 °C, and suit an unheated sub-tropical tank. The mistake is keeping them too hot — above about 25 °C they show laboured breathing, so do not house them with discus.

What is the difference between a pearl danio and a zebra danio?

The zebra danio carries bold dark-blue stripes the full length of the body, while the pearl danio is plain with a pearly violet-pink iridescent sheen and at most a faint posterior stripe. The pearl danio is also distinctly larger, about 5.5 cm versus roughly 4 cm.

How many pearl danios should I keep?

Five or six is the bare minimum, but eight to ten or more is the real target. A proper group spreads the normal playful chasing, stops the fish hovering nervously in the corners, and brings out the confident swimming and colour the species is known for.

What fish can live with pearl danios?

Match their energy: other robust, active community fish — medium cyprinids, tetras, livebearers, rainbowfish and peaceful bottom-dwellers like Corydoras and loaches. Avoid slow, timid or long-finned fish such as bettas, fancy guppies and slow gouramis, which get out-competed at feeding and stressed by the constant fast motion.

Do pearl danios jump?

Yes — they are accomplished jumpers that will leap at surface food, so a tight-fitting lid is mandatory and worth keeping closed especially right after feeding. An open or gappy top will eventually cost you fish.

Sources & confidence

Sources & confidence (9 species)

These back the Pearl Danio figures and the previewed tank mates above. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.

• Pearl Danio Danio albolineatus — Seriously Fish (seriouslyfish.com/species/danio-albolineatus) high confidence
• Amano Shrimp Caridina multidentata — Aquarium Co-Op amano shrimp care; Aquadiction high confidence
• Bamboo Shrimp (Wood/Fan Shrimp) Atyopsis moluccensis — Aquariadise (aquariadise.com/caresheet-bamboo-shrimp-atyopsis-moluccensis) high confidence
• Black Neon Tetra Hyphessobrycon herbertaxelrodi — Seriously Fish / Aqua-Fish (Hyphessobrycon herbertaxelrodi) high confidence
• Black Phantom Tetra Hyphessobrycon megalopterus — Seriously Fish (Hyphessobrycon megalopterus) high confidence
• Boesemani Rainbowfish Melanotaenia boesemani — Seriously Fish; Aquarium Co-Op Boesemani guide high confidence
• Bolivian Ram Mikrogeophagus altispinosus — Seriously Fish (seriouslyfish.com/species/mikrogeophagus-altispinosus) high confidence
• Brilliant Rasbora Rasbora einthovenii — Seriously Fish (seriouslyfish.com/species/rasbora-einthovenii) high confidence
• Bronze Corydoras Corydoras aeneus — Seriously Fish (seriouslyfish.com/species/corydoras-aeneus) high confidence

Care-guide sources (6)

This guide synthesises the references below; where they disagree, the range and the disagreement are noted in the text above. The figures in the key-facts box are read from the TankStocking species database (v2026.06). Full welfare model on the methodology page.

• Seriously Fish — Danio albolineatus — authority (Blyth 1860), Brachydanio header, SE Asia range, biotope (clear streams to rice paddies), wild water 16-25 C / pH 6.0-8.0 / 18-357 ppm, 50-55 mm SL, 90x30 cm base, group of 8-10, 'very peaceful', accomplished jumper, chiefly insectivorous, sexing, egg-scatterer no parental care, hatch 24-36 h
• FishBase — Danio albolineatus — Blyth 1860, family Danionidae, max 9.6 cm TL / common 3.4 cm SL, SE Asia range, freshwater benthopelagic, temp 20-25 C, pH 6.0-8.0, dH 5-19, diet insects + zooplankton, trophic 3.0, IUCN Least Concern, husbandry 'groups of 5 or more / minimum 60 cm'
• Wikipedia — Pearl danio — Blyth 1860, Brachydanio albolineatus synonym, family Danionidae, max 6.6 cm, iridescent colour + stripes, gold = semi-albino, lifespan ~5 years, surface/hill-stream habitat, pH 6.0-8.0, 5-19 dGH, 68-77 F, egglayer
• TFH Magazine — Danio albolineatus: a Classic Community Fish — typical 5 cm (to 6.4 cm), temp 68-77 F with overheating warning, wide pH/hardness, 20-gal-long minimum, groups of 5+, highly active fast feeder that leaps at surface food (lid after feeding), avoid small slow passive tankmates, iridescent purple/pink colour, gold form
• Aquadiction — Pearl Danio profile — min 75 L (prefers 110-285 L), max 6.5 cm, ~5 yr, 15-25 C / 60-77 F, pH 6.0-8.0, GH 5-19, groups of 6+, peaceful shoaler, tankmates (cyprinids/tetras/livebearers/rainbowfish/anabantoids/catfish/loaches), dither fish, egg-scatterer
• Care-guide search consensus (aqua-fish.net, fishncare.com, fishlaboratory.com) — 20 gal / elongated 'length over height' tank, 20-25 C, pH ~6.1-7.9, schools of 6+, hardy/beginner-friendly, ~5 yr lifespan (corroboration only; hard numbers anchored to Seriously Fish and FishBase)

More on Pearl Danio

Related guides on TankStocking — each scored by the same welfare engine as the planner.

This care guide is a sourced planning reference, not veterinary advice — individual fish, filtration and maintenance all matter. Cycle the tank, test your water, and observe your fish. How TankStocking works →