Zebra Danio
Danio rerio
Tireless striped swimmer for cooler tanksBeginner
- Lifespan
- 3-5 years
- Size
- 4-5 cm / 1.5-2 in
- Social needs
- Shoaler; keep 6+ together
- Time
- Low; daily feeding, weekly water change
- Cost
- Low
- Diet
- Omnivore; flakes, micro pellets, frozen foods
Overview
What is this animal?
- The zebra danio is a small, fast minnow from the streams and floodplains of South Asia, marked with horizontal blue-gold stripes.
- Widely used as a laboratory model organism, it is one of the hardiest and most adaptable aquarium fish available.
- It is an excellent beginner species, tolerant of a wide temperature range including cooler rooms.
- Avoid dyed or hybrid colour variants where possible, and never keep it in a tiny tank, as its constant activity demands swimming space.
Temperament
- Active, peaceful and confident, zebra danios shoal loosely and dash around the upper levels of the tank.
- Their speed and constant motion can unsettle very timid or slow species in a community.
- They can nip long, flowing fins when understocked, so keep six or more to channel that energy within the group.
- Pair them with similarly active, sturdy fish rather than delicate or long-finned tankmates such as bettas or fancy guppies.
A good fit for
- Beginners wanting a tough, lively first fish
- Unheated, room-temperature aquariums
- Active community tanks with sturdy species
- Keepers who enjoy constant movement
Common mistakes to avoid
- Cramped tanks restricting their fast swimming
- Keeping them too warm, shortening lifespan
- Fin-nipping when kept in too-small groups
- Open tanks they readily jump out of
Enclosure
Minimum 75 litres (20 US gallons) — for a group of 6
Cannot be kept alone. The minimum is 6, and the space above is for that group.
- Keep a shoal of at least six in 75 litres (20 gallons) or more, well filtered.
- They thrive at 18-24C and do not strictly need a heater in a stable, room-temperature home, which suits unheated setups in temperate climates.
- These are powerful, restless swimmers that need length rather than height for laps along the tank.
- They tolerate a wide range of water chemistry and appreciate some current and a secure lid, as they are accomplished jumpers.
Supplies
Setup
- Tank and stand
- Filter
- Heater and thermometer
- Substrate, plants and decor
- Liquid test kit
- Dechlorinator and starter supplies
Ongoing
- Quality tropical flake or micro-pellet
- Frozen daphnia
- Frozen brine shrimp
- Frozen or freeze-dried bloodworm
- Spirulina or vegetable flake
- Small feeding spoon for measured pinches
- Fine net for removing leftovers
Safe substrate: Inert aquarium gravel · Fine, smooth sand · Aquasoil for planted tanks
Care routine
Daily
- Check temperature and equipment
- Feed
- Head-count and look everyone over
Weekly
- Top up evaporationevery 3 days
- Check the lid
- Clean glass and clear algae
- Test the water
- Water change and gravel vacuum
Monthly
- Trim and thin the plantsevery 2 weeks
- Check supplies and reagent dates
- Rinse the filter media
Less often
- Replace chemical filter media (Carbon/Purigen)every 2 months
Vet: Quarterly temperature and stocking review — every 3 months
Top resources for more info
Independent creators and organisations we would send a friend to. We have no affiliation with any of them, and nothing here is sponsored. Links checked 2026-09-19.
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Diet
- Zebra danios are opportunistic omnivores that feed at the surface and in midwater.
- A quality flake or micro-pellet works as the staple, supplemented with frozen or live daphnia, brine shrimp and bloodworm for variety.
- Feed small amounts once or twice daily, only what is taken in a minute or two.
- Their fast metabolism and constant activity mean they rarely refuse food, so portion carefully to avoid overfeeding and fouling the water.
Health
- Danios are robust and disease-resistant, with most ailments arising from overcrowding, poor water quality or excessive heat rather than the fish themselves.
- Ich and fin rot are the usual concerns and clear readily with corrected conditions.
- Keeping them too warm for long periods can shorten their lifespan, so avoid over-heating the tank.
- Quarantine new arrivals, maintain weekly partial water changes, and fit a tight lid, since stress can prompt jumping.
Is your enclosure big enough?
Is this urgent?
In a fish tank the patient is usually the water. Test before you treat — dosing a healthy tank for a disease it does not have makes things worse.
Go now
Today
Soon
Never add a new fish to a tank that is not fully cycled, and never treat blind. A test kit is cheaper than the fish.
This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.
What it really costs
Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.
Bedding and substrate
Substrate in an aquarium is a filter as much as a floor. Most of the biology lives in and on it.
Safe
With a caveat
Never
This is our general list for freshwater fish. We have not built one specific to Danios & Minnows yet.
My kit says 0.25 ppm. Is that dangerous?
A liquid kit measures total ammonia, but only the un-ionised fraction is really toxic, and that fraction is governed by pH and temperature — each whole pH unit multiplies it roughly tenfold. So the same reading can be nearly harmless in one tank and lethal in another; this works out which one you are in.
Compare with other animals
The same axes for every animal, side by side — the way the guides are written makes that a fair comparison rather than two articles.
Danios & Minnows, side by side
Same axes, same care guides — the honest way to choose between types.
See all Danios & Minnows side by side →
