Zebra Danio (Zebrafish) Fish Species Profile

Zebra danios are a favorite of freshwater fish hobbyists because of their ease of care. They are also prolific breeders and the easiest type of egglayers to breed. With their attractively striped, black and white zebra-patterned bodies, these fish are easy to recognize. Zebrafish are very durable and can withstand an impressive range of water temperatures and conditions. They will generally do just fine without a water heater as they are comfortable at temperatures down to the low 60s F.

Species Overview

Common Names: Striped danio, zebra danio, zebrafish

Scientific Name: Danio rerio

Adult Size: 2 inches

Life Expectancy: 5 years

Characteristics

Family	Cyprinidae
Origin	Eastern India
Social	Peaceful, suitable for community tanks
Tank Level	All levels
Minimum Tank Size	10 gallon
Diet	Omnivore
Breeding	Egglayer
Care	Easy
pH	6.5 to 7.0
Hardness	5 to 12 dGH
Temperature	64 to 74 F (18 to 24 C)

Origin and Distribution

Zebra danios were originally thought to have originated from a wider range that stretched from Myanmar in the east and Pakistan in the west; however, the current consensus is that this species originates from a much narrower range that is confined to parts of India and Bangladesh.

Part of this change in distribution is due to the identification of similar species that were once misidentified as being Danio rerio. Damage to the environment that resulted in a reduction of habitable areas has also narrowed their natural range, even though wild zebra danios utilize a variety of habitats, ranging from fast-moving streams to slow-moving, nearly stagnant ponds.

Zebra danios available in the aquarium industry are now almost always captive-bred as zebras are easy and inexpensive to raise. While commercial breeding has provided a large and unlimited supply of this species, it has also resulted in a fish that is less robust than the original wild species. Many varieties of zebra danios are available now at your local aquarium store.

Colors and Markings

The zebra danio is easily recognized by its distinctive horizontal stripes. Blue-purple horizontal stripes run from gill to tail, setting off the slim, compressed, silver-gold body of this attractive fish.

Albino, golden, veil-tailed, and long-finned zebra danio varieties are available, as well as a popular leopard variety. The leopard strain is characterized by a sprinkling of black spots over the entire body. In the past, the leopard danio was considered a different species, but genetic studies have proven that it is merely a spotted variation of Danio rerio.

A brightly colored variety of zebra danio is now available called GloFish. These fish have had fluorescent pigment introduced into their DNA that makes them brightly colored. They still have the dark stripes but the body color is now orange, green, blue, purple or red.

Tankmates

The small size of the zebra danio, no more than two inches, makes them well suited to a community aquarium. Zebra danios are peaceful fish that get along with most tankmates, however, they will nip fins of some species. Any fish with long-flowing fins, such as angelfish, bettas, and guppies, are potential targets of the active zebra danio. Good potential tankmates may include similar-sized danios, barbs, corydoras catfish, tetras, loaches, mollies, platys and swordtails.

All varieties thrive in schools and should never be kept as singles. They do best when kept in a school of five or more of their own kind. Groups of this fish can be hierarchal, and a pecking order may emerge in the school, but there is no fighting. Select tankmates that are similar in temperament and that can keep up with the fast-paced behavior of this danio. Mellower fish that need a less hectic environment can become stressed in their presence.

Zebra Danio Habitat and Care

Zebras are primarily surface-dwelling fish that favor moving waters. Technically considered a cold-water fish, this fish prefers water in the 64 to 75 F range. However, they will adapt to a wide range of water conditions. If water temperatures are kept too low, they tend to become more susceptible to disease.

Zebras are extremely active, and although they have a preference for the upper levels of the aquarium, they will move throughout the entire tank. Provide them with diffuse lighting and an open swimming space with vegetation around the periphery of the habitat. A darker color substrate will help showcase the color of these fish and give the habitat a more natural feel.

The Spruce / Madelyn Goodnight

Zebra Danio Diet and Feeding

Zebra danios are omnivorous, accepting almost any food. Although undemanding in diet, they particularly enjoy small, live, or frozen invertebrates and fresh vegetable matter. They can be fed small pelleted food or flake fish food for their main diet, with supplements of freeze dried bring shrimp or tubifex worms, or frozen foods.

Gender Differences

Both sexes have two pairs of barbels and the same stripes, but females are usually larger. Males are a bit smaller and more slender than females. Male zebras appear more torpedo-shaped, while females tend to have a larger belly. More full-bodied than the males, a female’s belly balloons when it fills with eggs.

Breeding the Zebra Danio

Zebra danios are ideal for beginners as they are prolific breeders, and interestingly females can spawn every two to three days after reaching sexual maturity at about four months. The best way to obtain a mating pair is to start with a school of a half dozen or more young zebras and allow and watch for the females to develop rounded bellies. When the females are full of eggs, separate one or two females and two to four males into a separate breeding tank.

Set up a separate breeding tank with shallow water, approximately six inches deep. Furnish the tank with fine-leafed plants. The bottom needs to be covered with a coarse substrate such as marbles or large gravel/pebbles so that the eggs will fall between the substrate pieces and will be protected from the adult fish, which will readily eat their own eggs once they lay them. A wide-mesh breeding net holding the adults can also be suspended in the tank. The mesh needs to be large enough for the eggs to fall through the netting, without letting the parents out.

When preparing to breed them, providing a water change can help induce spawning. Spawning requires temperatures of up to 78 to 80 F and can be triggered by raising the water a few degrees near dawn, when spawning normally occurs. About 300 to 500 eggs will be scattered across the bottom and on the plants. Remove breeders after spawning, as they will also consume the young as they hatch.

The fry will hatch in about two days, depending on water temperature. The fry are very tiny and can easily be lost when changing water, so take care when maintaining the nursery tank. A sponge filter is best to use in the breeding/nursery tank so the babies do not get sucked into the filter. Feed the young commercially prepared fry food or finely crushed flake foods. You can also add a powdered egg to fry food to promote growth. Be sure not to overfeed as uneaten food will foul the water quickly.

More Pet Fish Breeds and Further Research

If zebra danios appeal to you, and you are interested in some compatible fish for your aquarium, check out:

Check out additional fish species profiles for more information on other freshwater fish.