Spotted Danio Fact Sheet

The Spotted Danio, Danio nigrofasciatus, is a peaceful little fish from Myanmar.  It is also called the Dwarf Danio.

Length and Longevity

The Spotted Danio will grow to about 4 cm long although the great majority of them never reach this size. They can live for 3 years.

This fish will live happily in temperatures between 18 and 26 degrees C (between 64 and 79 degrees F) although they can certainly survive outside this range, but their tolerance of extremes of high and low temperatures appears to be somewhat less than the extreme temperature tolerance of the Zebra Danio.  In their native habitat they live in monsoonal rivers with low water during the hot season in March and April so the water can get quite hot.  When the monsoon rains come, starting in about May, the water is much cooler, so they have to be able to take both extremes.  The Spotted Danio is a tropical fish that can take cooler temperatures than the typical tropical fish.

They will cope with both soft and with moderately hard water.  The ideal ph is neutral to slightly acid although they have a moderate tolerance to alkaline water as well.

This fish mainly lives in smaller streams, ditches, flooded rice fields and ponds rather than the big rivers of Myanmar.  Although they can take a reasonable current they do not come from raging torrents and some calm areas in the aquarium are a good idea.

Plants

This is a shy fish that will benefit from the cover provided by some plants in the aquarium. I suggest that a very well planted tank is ideal.

Jumping

The Spotted Danio is one of the fish that has the reputation of being able to jump out of an aquarium so a tightly fitting lid is a good idea.

Food

The Spotted Danio is an omnivore which adapts readily to normal aquarium foods such as good quality flakes.  As with most animals they benefit from a variety of food.  Frozen bloodworms are eaten avidly, but this fish does not eat as much at one time as some of its near relatives.  This fish mostly eats at the surface of the water and in the upper half of the tank.  Live food including Mosquito larvae and Daphnia are good for this fish.

Companions

The Spotted Danio is a schooling fish and ideally there should be enough together to form a large school.  Although they will form a school with as few as 4 fish, 8 would be a much better number.  The will live with other small peaceful; fish like the smaller tetras and Rasboras.  They do not usually nip fins although this has been known to happen, so I would avoid putting them with slow moving fish with long fins like Guppies and Siamese Fighting Fish.

They are also compatible with the Corydoras catfish.

Sexing

The males are slimmer and more colourful than the females.  When they are fully grown, the female are a little larger than the males.

Semi-natural Breeding

This is an easily spawned egg layer, but the females do not lay as many eggs at one time as some of the other Danios, and each female will often lay less than 50 eggs at one time rather than the hundreds of eggs that many other Danios lay at a time.

This is one of the types of fish that will spawn frequently without their owner being aware of it.  They eat their own eggs and babies and usually none of the young will survive in a normal aquarium.  However, in a densely planted aquarium that is very lightly stocked with fish there is a good chance of some fry surviving.  This is the closest most people will be able to get to natural breeding of this fish.  This is also probably the best way of producing strong young fish.  In the wild, on average, each fish will only have two babies that survive long enough to reproduce so by saving most of the baby fish we are doing something not completely natural.

Breeding Tank

People who want to save more of the fry would usually set up a special breeding tank.  The fish should be conditioned by frequent feeding of rich foods.  This can be done with the fish in a school before putting them into the breeding tank.

Generally a dimly lit small tank is used as a breeding tank with shallow water, often starting off  only 3 or 4 inches deep.  Like other Danios, the Spotted Danio will eat its own eggs as well as those of other types of fish, so the bottom of the tank needs something on it to prevent most of the eggs being eaten.  A thick layer of marbles is an old solution to this problem.  The same can be done with round pebbles of about 9 mm.  Breeding grass or mops will also work.  Some people prefer real plants for this and use Java Moss or similar plants.

Slightly acidic water is normally used with a temperature around 26 degrees C (79 degrees F).  A current of water can be provided by a small power filter.  Some people like to stimulate spawning by simulating the start of the monsoon with sprinklings of cool rain water over the surface of the water in the tank.

The adults should be removed after spawning. The eggs hatch in 24 to 36 hours, hatching a little faster at higher temperatures.  Bright light should be avoided during hatching.

Raising the Babies

The natural food of baby fish as small as those of the Spotted Danio is generally paramecia and other protozoa, usually referred to as infusoria.  In the semi natural breeding method, the fry usually find enough of the micro-organisms in the aquarium.  When the larger numbers of babies are present in a special breeding tank, the infusoria will need to be added.  These can be supplemented with commercial dry or liquid commercial fry food of a small size.  Another method of feeding baby fish was hard boil an egg yolk forced through a coarse cloth so it forms a suspension in water.  Frequent feeding is necessary, but care must be taken to avoid polluting the tank water with too much uneaten food.

As the fry get bigger, other types of live food such as screened Daphnia and newly hatched Brine Shrimp can be given to them.

Conservation Status

The Spotted Danio has not been assessed for the UINC Red List, but commercial and other evidence suggests that it is not in any immediate danger of extinction.

Common Names

Other names for the Spotted Danio in English include “Dwarf Danio” and “Dwarf Spotted Danio”.

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Scientific Names

The accepted scientific name for this species is Danio nigrofasciatus, (Day, 1870).  Other names which have been used include Barilius nigrofasciatus (Day, 1870), Brachydanio nigrofasciatus (Day, 1870) and Danio analipunctatus (Boulenger, 1911).

Pest Fish

Although this is a peaceful little fish, as with all animals, care should be taken to avoid it being introduced into environments that it is not native to.

Steve Challis