Photo: Marrabbio2 (Public domain) — via Wikimedia Commons
Zebra Danio (Danio rerio)
A tireless, hardy little torpedo with go-faster stripes — the bombproof shoaler that breaks in a new tank.
Will it live with a Zebra Danio?
We compare each fish against your zebra danio on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Adolf's Cory✅ CompatiblePeaceful · 5.5 cm · Medium care · 22–26 °C (72–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Adolf's Cory in a shoal of 6+ or it gets stressed and nippy.
- Axelrod's Cory✅ CompatiblePeaceful · 5 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Axelrod's Cory in a shoal of 6+ or it gets stressed and nippy.
- Bandit Corydoras✅ CompatiblePeaceful · 5 cm · Easy care · 22–27 °C (72–81 °F)
- Compatible on the things that matter: shared water near 22–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Bandit Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Bloodfin Tetra✅ CompatiblePeaceful · 5.5 cm · Easy care · 18–28 °C (64–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Blue Turbo Snail✅ CompatiblePeaceful · 5 cm · Medium care · 25–30 °C (77–86 °F)
- Both are peaceful, and their water overlaps around 25–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Checkered Barb✅ CompatiblePeaceful · 5 cm · Easy care · 20–25 °C (68–77 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Checkered Barb in a shoal of 6+ or it gets stressed and nippy.
- Cherry Barb✅ CompatiblePeaceful · 5 cm · Easy care · 23–27 °C (73–81 °F)
- Both are peaceful, and their water overlaps around 23–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Cherry Barb in a shoal of 6+ or it gets stressed and nippy.
- Cochu's Blue Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Cochu's Blue Tetra in a shoal of 8+ or it gets stressed and nippy.
- Firehead Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Firehead Tetra in a shoal of 8+ or it gets stressed and nippy.
- Five-banded Barb✅ CompatiblePeaceful · 5 cm · Easy care · 23–27 °C (73–81 °F)
- Compatible on the things that matter: shared water near 23–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Five-banded Barb in a shoal of 6+ or it gets stressed and nippy.
- Forktail Blue-eye✅ CompatiblePeaceful · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–25 °C — no size, zone or temperament conflicts.
- Both favour the top of the tank — offer enough cover so they aren't always in each other's space.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Forktail Blue-eye in a shoal of 6+ or it gets stressed and nippy.
- Half-striped Penguin Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Half-striped Penguin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Harlequin Rasbora✅ CompatiblePeaceful · 5 cm · Easy care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Honey Gourami✅ CompatiblePeaceful · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Horseman Cory✅ CompatiblePeaceful · 5 cm · Medium care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Horseman Cory in a shoal of 6+ or it gets stressed and nippy.
- Japanese Trapdoor Snail✅ CompatiblePeaceful · 5 cm · Easy care · 10–28 °C (50–82 °F)
- Both are peaceful, and their water overlaps around 18–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Julii Corydoras✅ CompatiblePeaceful · 5 cm · Easy care · 23–26 °C (73–79 °F)
- Both are peaceful, and their water overlaps around 23–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Julii Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Masked Corydoras✅ CompatiblePeaceful · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Masked Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Mystery Snail✅ CompatiblePeaceful · 5 cm · Easy care · 20–28 °C (68–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Panda Corydoras✅ CompatiblePeaceful · 5 cm · Medium care · 20–26 °C (68–79 °F)
- Compatible on the things that matter: shared water near 20–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Panda Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Rummy-nose Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 23–29 °C (73–84 °F)
- Both are peaceful, and their water overlaps around 23–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Rummy-nose Tetra in a shoal of 6+ or it gets stressed and nippy.
- Skunk Corydoras✅ CompatiblePeaceful · 5 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Skunk Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Stoliczka's Barb✅ CompatiblePeaceful · 5 cm · Easy care · 20–26 °C (68–79 °F)
- Both are peaceful, and their water overlaps around 20–25 °C — no size, zone or temperament conflicts.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Stoliczka's Barb in a shoal of 6+ or it gets stressed and nippy.
- Xingu Black Neon Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Amano Shrimp⚠️ With cautionPeaceful · 5 cm · Easy care · 18–28 °C (64–82 °F)
- Adult Amano Shrimp might survive with Zebra Danio, but expect the young to be eaten — plant heavily.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Black Ruby Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Black Ruby Barb is semi-aggressive and may chase or nip the smaller Zebra Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Black Skirt Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Black Skirt Tetra is semi-aggressive and may chase or nip the smaller Zebra Danio — plant heavily and break up sight lines.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Chocolate Gourami⚠️ With cautionPeaceful · 5 cm · Hard care · 25–30 °C (77–86 °F)
- pH preferences only just meet (Zebra Danio 6.5–7.5 vs Chocolate Gourami 4–6) — target the overlap and acclimate slowly.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Chocolate Gourami in a shoal of 6+ or it gets stressed and nippy.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Expect Desert Goby to harass Zebra Danio at times; give dense cover and watch them at feeding.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Dwarf Chain Loach⚠️ With cautionPeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
- Eastern Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Eastern Betta and Zebra Danio are close in size, but the semi-aggressive one tends to dominate — add zebra danio in a group to spread the pressure.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- GloFish Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
- Expect GloFish Tetra to harass Zebra Danio at times; give dense cover and watch them at feeding.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep GloFish Tetra in a shoal of 6+ or it gets stressed and nippy.
- Humpbacked Tetra⚠️ With cautionSemi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Expect Humpbacked Tetra to harass Zebra Danio at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Humpbacked Tetra in a shoal of 8+ or it gets stressed and nippy.
- Morse Code Corydoras⚠️ With cautionPeaceful · 5 cm · Medium care · 23–26 °C (73–79 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Morse Code Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Odessa Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Expect Odessa Barb to harass Zebra Danio at times; give dense cover and watch them at feeding.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Odessa Barb in a shoal of 6+ or it gets stressed and nippy.
- Peaceful Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Expect Peaceful Betta to harass Zebra Danio at times; give dense cover and watch them at feeding.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Silvertip Tetra⚠️ With cautionSemi-aggressive · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Silvertip Tetra and Zebra Danio are close in size, but the semi-aggressive one tends to dominate — add zebra danio in a group to spread the pressure.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Keep Silvertip Tetra in a shoal of 6+ or it gets stressed and nippy.
- Spotfin Betta⚠️ With cautionSemi-aggressive · 5 cm · Medium care · 23–28 °C (73–82 °F)
- Spotfin Betta is semi-aggressive and may chase or nip the smaller Zebra Danio — plant heavily and break up sight lines.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Striped Red-Eye Puffer⚠️ With cautionAggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Striped Red-Eye Puffer is aggressive and may chase or nip the smaller Zebra Danio — plant heavily and break up sight lines.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Wine Red Betta⚠️ With cautionAggressive · 5 cm · Medium care · 24–28 °C (75–82 °F)
- One likes softer water and the other harder (5–15 vs 0–4 dGH) — a compromise, not a perfect match.
- Wine Red Betta and Zebra Danio are close in size, but the aggressive one tends to dominate — add zebra danio in a group to spread the pressure.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Alligator Gar (250 cm) is big enough to swallow the 5 cm Zebra Danio whole.
- Alligator Gar is aggressive and may chase or nip the smaller Zebra Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Size gap is too large (90 vs 5 cm): Clown Knifefish will treat Zebra Danio as food.
- Clown Knifefish is aggressive and may chase or nip the smaller Zebra Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Size gap is too large (100 vs 5 cm): Fire Eel will treat Zebra Danio as food.
- Expect Fire Eel to harass Zebra Danio at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Zebra Danio is bite-sized to a 90 cm koi — it will be eaten.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Zebra Danio is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
- Expect Redtail Catfish to harass Zebra Danio at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Size gap is too large (90 vs 5 cm): Spotted Gar will treat Zebra Danio as food.
- Expect Spotted Gar to harass Zebra Danio at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Zebra Danio is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
- Wels Catfish is aggressive and may chase or nip the smaller Zebra Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Wolf Cichlid (72 cm) is big enough to swallow the 5 cm Zebra Danio whole.
- Wolf Cichlid clearly outsizes Zebra Danio and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Zebra Danio care specs
- Care level
- Easy
- Breeding
- Easy
- Max size
- 5 cm (2 in)
- Min tank size
- 75 L (19.8 gal)
- Temperature
- 18–25 °C (64–77 °F)
- pH
- 6.5–7.5
- Hardness
- 5–15 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Top
- Group size
- 6+ (shoaling)
- Family
- Cyprinidae
- Origin
- South Asia — India, Bangladesh and Nepal
What is a Zebra Danio?
The zebra danio (Danio rerio) is a small, endlessly energetic shoaling fish from South Asia, instantly recognisable by its horizontal blue-and-gold stripes that run from nose to tail. Adults top out at about 5 cm (2 in), but their personality outpaces their size considerably. They move in restless, darting bursts near the surface and rarely pause.
Beyond the home aquarium, the zebra danio is one of the most studied vertebrates in science — its transparent embryos and fast generation time have made it a workhorse of genetics and developmental biology research. That same hardiness translates directly to the hobby: it survives a wide range of water conditions, tolerates cooler temperatures, recovers from mistakes that would kill softer fish, and ships and acclimates easily. It has been a standard recommendation for fishkeeping beginners for decades, and the recommendation holds up. Selective breeders have produced long-fin, leopard-patterned, and fluorescent “GloFish” strains, but the care for all of them is the same.
Where do Zebra Danios come from?
Zebra danios are native to South Asia — primarily the river systems of India, Bangladesh and Nepal, with records extending into parts of Pakistan, Bhutan and Myanmar. In the wild they occupy shallow, sun-drenched streams, rice paddies and roadside ditches where water moves with moderate current and temperatures drop with the seasons. These habitats are often exposed, with a mix of silt and gravel substrate and patches of aquatic vegetation along the margins.
The key ecological detail is that wild populations regularly experience cooler seasons. Water temperatures in their Himalayan-foothill range dip well below what most tropical aquarium fish could tolerate, which is why the zebra danio’s temperature band (18–25 °C / 64–77 °F) extends so far into the cool end. This adaptability is the root of their aquarium hardiness — they are genuinely accustomed to variable conditions, not just tolerant of them in a pinch.
What size tank does a Zebra Danio need?
The minimum is 75 litres (20 gallons), and the shape of the tank matters as much as the volume. Zebra danios are fast, open-water swimmers that spend most of their time near the surface. They need horizontal length, not height — a long, shallow footprint lets them sprint, turn and school properly. A standard 90 cm (36 in) or longer tank suits them far better than a tall hexagonal of the same volume.
A tight lid is non-negotiable. Zebra danios are well-documented jumpers, especially when startled, and they are quick enough to find any gap. A standard power filter providing moderate current is appropriate; they are comfortable in flowing water and don’t need the near-still conditions that bettas or gouramis prefer. Substrate, decor and plants are largely a matter of taste — the fish are active and largely indifferent to aquascape style as long as there is open swimming space in the midwater and upper zones.
What water parameters do Zebra Danios need?
- Temperature: 18–25 °C (64–77 °F). A heater is optional in a reliably warm room; in most households the ambient temperature sits within range year-round, which is one of the species’ real practical advantages. Do not pair them with fish that need 27–30 °C.
- pH: 6.5–7.5, leaning neutral.
- Hardness: 5–15 dGH, soft to moderately hard.
These numbers describe a forgiving window, not a knife-edge target. The usual aquarium-keeping fundamentals still apply: cycle the tank before adding fish, do regular partial water changes, and avoid sudden swings. Danios tolerate a range well but are not immune to ammonia spikes or temperature shocks. The cooler temperature ceiling is worth emphasising — if you add a heater, keep it set no higher than 25 °C so it does not suppress immune function over time.
What do Zebra Danios eat?
Zebra danios are omnivores and undemanding feeders. A quality small-pellet or micro-granule staple covers the nutritional base; supplement it with frozen or live foods — daphnia, baby brine shrimp, bloodworms and tubifex — to maintain condition and colour. They feed at the surface and upper water column and will also take flake readily.
Feed small amounts once or twice a day. Their activity level means they burn energy quickly, but overfeeding still degrades water quality, and danios will eat past satiation without stopping. A good rule is to offer what the shoal consumes in two or three minutes and remove any excess. The variety matters more than precise ratios: rotating protein-rich live or frozen foods with a plant-based pellet covers their omnivore needs well.
Are Zebra Danios aggressive — and what fish can live with them?
Zebra danios are peaceful in the sense that they are not territorial or predatory, but they are fast, active and boisterous — qualities that can stress quieter, slower or more delicate tank-mates. In an undersized group, especially below six fish, they may redirect their energy into fin-nipping at slow, long-finned species like bettas, guppies or angelfish. A full shoal of six or more occupies itself with schooling and leaves tank-mates alone.
Good companions are similarly active, similarly sized community fish: other danio species, rasboras, tetras, corydoras and loaches that can hold their own in an energetic tank all work well. Avoid pairing them with bettas (temperature incompatibility and fin-nipping risk), discus (temperature and sensitivity mismatch), or very small nano fish that could be outcompeted at feeding time.
For a full pairing list, see Zebra Danio tank mates.
How do you tell male and female Zebra Danios apart?
Sexing zebra danios is straightforward once you know what to look for, and easiest when comparing fish side by side in the same tank. Females are noticeably larger and rounder-bellied, particularly when conditioned on good food; the abdomen has a gentle convex curve that becomes pronounced when a female is carrying eggs. Males are slimmer — almost torpedo-shaped — and carry a warmer golden tone through their stripes compared to the slightly cooler blue-silver of females. The difference is subtle in juveniles but becomes clear in adults of 2–3 cm and above.
How do Zebra Danios breed?
Zebra danios are egg scatterers and among the easiest aquarium fish to breed, which is part of why they are so well understood in the lab. A conditioned pair or group will spawn readily without any intervention beyond good feeding and a slight temperature rise — and because the fish eat their own eggs enthusiastically, the challenge is not triggering spawning but preserving the eggs afterward.
The standard method is to set up a shallow breeding tank with a mesh or marbles on the bottom (so eggs fall through out of reach), introduce a well-fed group of adults in the evening, and remove the adults in the morning after spawning. Eggs hatch in roughly two days at 25 °C, and the fry become free-swimming a day or two later. First foods are infusoria or commercial fry food, moving to baby brine shrimp as they grow. Growth is fast, and a clutch of healthy fry is a manageable project even for a first-time breeder.
What are common Zebra Danio diseases?
Zebra danios are robust, but they are not disease-proof. The most common issues are:
- Ich (white spot): Fine white grains on fins and body, often triggered by a temperature drop or introducing new fish without quarantine.
- Velvet: A dusty gold or rust sheen on the body, caused by a parasite; can spread quickly in a shoal.
- Fin rot: Ragged, receding fin edges — almost always linked to poor water quality or a secondary bacterial infection following injury from nipping.
- Dropsy (bloat): Raised scales and a swollen abdomen; a sign of internal infection or organ failure rather than a disease itself. Usually indicates a fish is seriously ill.
- Swim-bladder disorders: Erratic swimming or floating at the surface, often from overfeeding or a bacterial infection.
Prevention covers the majority of cases: maintain a cycled tank, keep temperatures stable, quarantine new fish and plants for two to four weeks, and feed a varied diet without overfeeding. A healthy, well-fed shoal in clean water is genuinely resistant to most outbreaks.
Health note: disease diagnosis and medication are beyond the scope of a care profile. Before treating, confirm the symptoms against a reputable veterinary or aquatic health source — misidentification leads to ineffective or harmful treatment.
How long do Zebra Danios live?
With good care, zebra danios live 3–5 years. That is a reasonable lifespan for a small cyprinid, and the upper end is achievable in a stable, well-maintained tank with a varied diet. Fish purchased from a pet store are typically juveniles, so you have most of those years ahead when you bring them home. The usual longevity killers are chronic temperature stress (either too cold from no heater control or too warm for the species’ range), overcrowding and the cumulative effect of poor water quality — all of which are straightforwardly preventable with basic husbandry.
Frequently asked questions
Do zebra danios need a heater?
Often not. They tolerate cooler water (18–25 °C) than most tropical fish, so in a warm room they can go unheated — which also makes them poor tank-mates for warmth-lovers like bettas and discus.
Are zebra danios fin-nippers?
They can be. They're fast and busy, and in too small a group they may nip slow, long-finned fish. Keep at least six and give them open swimming space to burn off energy.
What you need to keep a zebra danio
The baseline is a heated, filtered 75 L+ tank: a reliable heater to hold 18–25 °C (64–77 °F), a gentle filter that won't batter a zebra danio in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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