Assorted Danios (Danio spp.)

Choose assorted danios for a lively, hardy shoal

Assorted Danios are a random selection of small Danio species and colour forms, picked from the danios available when your order is packed. Danios are slim, fast, peaceful shoaling fish from South and Southeast Asia, and a group brings constant movement to the upper and middle water of a community aquarium. FishBase now places them in the family Danionidae; older books and many care sites still list them under Cyprinidae, the carp and barb family.

The common small danios are genuinely small. Seriously Fish gives the zebra danio a maximum of 5 cm standard length and the pearl and rosy danios 5.5 cm, while FishBase records the zebra danio at 3.8 cm. A mix of assorted danios is a good, economical way to start a busy shoal if you are happy not to choose the exact fish.

Decide from the complete care picture

Browse our rasboras and danios or go straight to the Danio genus category to compare named species. Our photographs show a typical striped danio for illustration, not the fish you will receive.

Understand what a random selection means

One purchase quantity supplies one live danio in a medium size grade, picked at random. Species, colour and pattern vary between fish and between orders, and you cannot choose them. The sex is not specified. Seriously Fish notes that mature females of these species are usually rounder-bellied, slightly less colourful and a little larger than males, but this is not something we can select for in a random mix.

If you want one particular look, buy a named fish instead, such as the Pearl Danio, Kerr's Blue Danio, Rosy Danio or Glowlight Danio.

Work from the shoal you intend to keep

• One selected unit: one danio, chosen at random.
• Eight selected units: the lower end of the Seriously Fish shoal recommendation of eight to ten.
• Ten or more: a fuller shoal, provided the aquarium and its existing fish can support the whole group.

Before you order, prepare the aquarium for the whole shoal and read our delivery and live arrival terms. The delivery day is not the right time to find that the planned shoal does not fit.

Meet the small danios most often sold

We cannot say which species will be in a given selection, but the small danios most often traded in the UK are close relatives with similar care. The table uses each species' Seriously Fish profile, so you can see how alike, and how slightly different, they are.

Zebra danios also come in ornamental forms. Seriously Fish describes the spotted leopard danio as a natural mutation of the striped form, and lists golden and long-finned varieties, all with the same care as the wild type.

Know the difference from giant danios

Giant danios belong to a different genus, Devario, and are not what this listing is for. Seriously Fish gives the giant danio Devario malabaricus 8 cm and a minimum base of 120 × 45 cm. If you would like one, our Giant Danio is sold separately with its own care notes.

Plan the aquarium around the adult shoal

Seriously Fish gives a minimum base of 90 × 30 cm, about 81 litres, for the zebra, pearl and rosy danios, and 80 × 30 cm for Kerr's and glowlight danios. With a random mix, plan for the larger figure. OATA gives at least 45 litres for a small shoal of the smaller species and at least 120 litres for larger danios of 5 cm or more; the length of the tank matters more than its height, because danios swim fast and constantly from end to end.

Use a three-step space check

1. Measure the base: at least 90 cm long and 30 cm from front to back.
2. Count complete groups: eight to ten danios plus the full intended number of every other shoaling species.
3. Plan for adult size: up to about 5.5 cm per danio, whatever size is supplied.

Our stocking calculator helps you check the full community, and our guide to setting up a first tropical aquarium explains how to prepare and mature the tank before fish arrive.

Arrange plants at the sides and keep the middle open

Seriously Fish says décor is not critical, but danios show better colour in a well-planted aquarium with a dark substrate, and floating plants and driftwood help to soften the light. They appreciate some water movement, though the filtration does not need to be strong.

Divide the footprint by function

Keep the aquarium covered, as you would for any active surface-swimming fish, and leave space at the back for a siphon so you can reach waste during water changes.

Set water values that suit every danio in the mix

Because you will not know exactly which species you receive, use the overlap of their ranges. Across the five species in the table, Seriously Fish's ranges overlap at 18–25°C, pH 6.5–7.5 and about 5–12 dGH. OATA's general danio guidance is a little wider: 17–27°C, pH 6.5–8.0, 4–12°dH general hardness and 3–10°dKH carbonate hardness.

UK tap water varies widely by region, from soft to very hard, so test yours and compare it with our water matcher. If your water runs a little above pH 7.5, Seriously Fish allows the zebra and pearl danio up to pH 8.0 and OATA gives 6.5–8.0 for danios generally; a stable reading matters more than chasing an exact number with chemicals.

Separate habitat values from waste readings

OATA sets the ammonia, nitrite and nitrate limits in its danio care sheet. In its guide to unheated aquaria, OATA says some danios, such as zebra and leopard danios, can live without a heater in an indoor aquarium, and advises asking about other species. With a random mix, the safe approach is a heater set to hold the tank at 18°C or above when the room is cold.

Filter for clean water and a gentle current

An active shoal needs clean, well-oxygenated water. Use a mature biological filter sized for the whole community, and direct the outflow along the length of the tank so the danios have a current to swim into while the planted ends stay calmer.

Follow a weekly maintenance sequence

1. Test ammonia, nitrite and nitrate at least once a week, and more often while the tank is new.
2. Change at least 25% of the water each week, as OATA recommends.
3. Treat new water with a tap-water conditioner and match its temperature.
4. Siphon waste from open areas of the substrate.
5. Rinse filter media in removed aquarium water, never under the tap, so the beneficial bacteria survive.

Feed small varied meals once a day

In the wild, danios are micropredators that eat small crustaceans and insects such as mosquito larvae. In the aquarium they accept most foods. Seriously Fish recommends a good dried food with small live or frozen foods such as Daphnia, brine shrimp and bloodworm, and OATA advises feeding once a day, only what the fish finish within a few minutes.

Build one measured meal

• Staple: a flake or small granule such as Supervit Mini Granulat, sized so the smallest fish can swallow it.
• Variety: frozen Daphnia or freeze-dried brine shrimp a few times a week, in place of part of the dry meal.
• Spread it out: scatter food along the surface so slower or smaller fish get a share.
• Stop in time: remove anything still uneaten after a few minutes.

Watch every fish at feeding time. In a mixed shoal the smallest species, such as glowlight danios, can lose out to bigger, bolder zebra or pearl danios, so a wider scatter of smaller food helps everyone feed.

Introduce the shoal to a mature aquarium

Before introducing danios, confirm that the filter is mature, ammonia and nitrite read zero, and the temperature is 18–25°C. OATA recommends switching off the aquarium lights, floating the sealed bag for 10 minutes, then adding small amounts of tank water to the bag over up to 20 minutes before releasing the fish with as little bag water as possible. Throw the bag water away.

Use a first-week checkpoint plan

Our step-by-step guide to acclimatising new fish covers the method in more detail. Add new fish to an existing community gradually, and retest after each addition.

Watch the shoal and act on changes

Healthy danios have clear, bright eyes, undamaged fins and scales, steady breathing and constant, purposeful swimming. Seriously Fish notes that the zebra danio has been mass-produced for so long that inbreeding is widespread, and it lists neon tetra disease (for which there is no effective treatment), columnaris (Flavobacterium columnare) and microsporidiosis, sometimes called "skinny disease", among the problems seen in the species. Buying from healthy stock and keeping a mature, clean aquarium are the best protection.

Pair each observation with an action

Our guide to white spot treatment explains one of the commonest problems in new community fish. Do not diagnose a disease from one sign alone: test the water first and note any recent change.

Keep eight to ten or more together

Seriously Fish says each of these danios should be kept in a group of at least eight to ten, and that males compete for females and show their best colours in a group. OATA gives a minimum of five and says more is better, warning that danios kept singly or in too small a group often become stressed.

A mixed group of danios makes a busy, colourful display. The shoal recommendations are written per species, though, so if you want a tight, uniform shoal, build it from one named species.

Read the breeding notes first

Danios are egg-scattering spawners with no parental care, and adults eat their own eggs. Seriously Fish describes breeding zebra danios in a small, dimly lit tank with mesh or fine-leaved plants such as Java moss to protect the eggs, with the adults removed after spawning; the eggs hatch in 24–36 hours. It also warns that pearl danios have been crossed with rosy danios by commercial breeders. With a random mix you cannot be sure which fish are which species, so for breeding, buy one named species.

Screen every tank mate before mixing

Seriously Fish describes the common small danios as very peaceful and lists other small cyprinids, tetras, livebearers, rainbowfish, gouramis and other labyrinth fish, catfish and loaches as suitable companions. OATA adds that their constant activity can stress timid fish, and that larger goldfish may eat small fish like these.

Use the same five questions every time

1. Do the water ranges overlap? The tank must stay within 18–25°C for the danios and within the companion's own range.
2. Will every shoaling species have its full group? Reserve room for eight to ten danios first.
3. Is any fish big enough to eat a danio? If so, leave it out.
4. Is any companion slow, shy or long-finned? Watch closely; busy danios can unsettle them.
5. Can every fish reach food? Bottom fish need sinking food that reaches them.

Our tank mates checker lets you test a combination before you buy, and our White Cloud Mountain Minnow guide covers one of the best cool-water partners for danios.

Answer assorted danio buying questions

Can I choose which danios I receive?

No. Assorted Danios are picked at random from the small danio species and colour forms available, so species, colour and pattern vary. To choose a particular kind, buy a named danio instead.

How many danios should I keep?

Seriously Fish recommends at least eight to ten for each of the common small danios, and OATA says at least five, with more being better. Each purchase quantity supplies one fish, so order eight or more for a shoal.

What size tank do assorted danios need?

Plan for a long aquarium with a base of at least 90 × 30 cm, about 81 litres, which is the Seriously Fish minimum for zebra, pearl and rosy danios. OATA gives at least 45 litres for a small shoal of the smallest species.

Do danios need a heater?

The common small danios suit 18–25°C. OATA says some, such as zebra and leopard danios, can live in an unheated indoor aquarium, but with a random mix use a heater whenever the room drops below 18°C.

What water conditions suit a mix of danios?

Aim for 18–25°C, pH 6.5–7.5 and about 5–12 dGH, where the Seriously Fish ranges of the common small species overlap. Keep ammonia and nitrite at zero and nitrate no more than 20 mg/l above your tap water.

Can different danio species live together?

Yes. They share similar needs and are very peaceful. Seriously Fish group advice is given per species, so a shoal of one named species gives the most natural display, and anyone planning to breed should keep species apart.

What do danios eat?

Almost anything of the right size. Feed a good flake or small granule once a day, only what the shoal clears in a few minutes, and add small live or frozen foods such as Daphnia, brine shrimp and bloodworm.

Are danios good for beginners?

Yes, they are among the hardiest community fish, provided the aquarium is mature, long enough for an active shoal, and kept clean with weekly testing and partial water changes.

Consult the care references

• Seriously Fish: Danio rerio (zebra danio) — size, aquarium, water range, diet, shoal size, compatibility, breeding, colour forms and common health problems in mass-bred stock.
• Seriously Fish: Danio albolineatus (pearl danio) — size, aquarium, water range, shoal size and notes on hybrids with D. roseus.
• Seriously Fish: Danio kerri — size, aquarium and water range.
• Seriously Fish: Danio roseus — size, aquarium and water range.
• Seriously Fish: Danio choprae — size, aquarium and water range.
• Seriously Fish: Devario malabaricus — the larger giant danio, for comparison.
• FishBase: Danio rerio — current family (Danionidae), maximum recorded length, wild water values and distribution.
• OATA: How to look after danios and white cloud mountain minnows — UK trade guidance on group size, tank size, water-quality limits, feeding, maintenance, acclimatisation and warning signs.
• OATA: Indoor coldwater fish (September 2022) — which danios can be kept in unheated indoor aquaria.
• GOV.UK: Freshwater fish that can be kept for ornamental purposes (list updated 13 October 2026) — lists the genus Danio under the general licence for indoor aquaria only (England and Wales).
• Tropical Fish Co delivery policy — current dispatch days and live arrival terms.