斑马鱼 · Zebra Danio

Overview

Active and generally undemanding, Danio rerio is a familiar community fish. Most aquarium zebrafish are farmed. Long-standing mass production has also produced variable stock quality, so inspect prospective purchases for normal shape and behavior.

Distribution & habitat

India and Bangladesh form the best-supported range, with Bhutan a possibility. Several older records from elsewhere appear to involve mistaken identities. Surveys have found the fish in quiet pools, established rice fields, and seasonal wetlands, often beside vegetation over silty ground. In flowing streams, they tend to use calmer margins.

Aquarium setup

Swimming activity makes tank length an important consideration despite the fish's modest size. Planting over a dark bottom can enhance the display, while floating leaves and wood break up incoming light. Some circulation is welcome, but powerful flow is unnecessary.

Diet & feeding

Wild stomach samples identify this fish as a predator of tiny animals, including crustaceans and mosquito larvae. Aquarium feeding is straightforward: combine a good prepared diet with suitably sized live or frozen prey, such as water fleas, brine shrimp, and bloodworms.

Behaviour & compatibility

A shoal of at least eight to ten helps reduce nervousness and encourages male display. Many small tetras, cyprinids, catfish, and loaches can be considered as companions after their environmental needs and adult sizes have been checked.

Sexual dimorphism

Females are usually fuller through the belly, somewhat larger, and less intensely colored. These differences become easier to see when females carry eggs and males develop breeding coloration.

Breeding

Eggs are scattered without subsequent parental care. A mature planted aquarium may produce a few surviving fry, while a separate spawning arrangement offers better control. Protect eggs with fine vegetation or a mesh floor inaccessible to the parents.

After conditioning, introduce one or two pairs. Small additions of cooler water, together with small live or frozen meals, may encourage spawning. Separate adults from their eggs and use established sponge filtration to protect larvae from pump intakes. Hatching commonly takes 24–36 hours; swimming follows a few days later. Offer microscopic starter food before graduating to microworms and brine shrimp nauplii.

Notes

The spotted leopard form is a spontaneous variation also found outside captivity. Golden and elongated-fin strains are among the ornamental forms. Watch for deformity, persistent wasting, bent spines, pale patches, or separation from the shoal. Several illnesses can produce overlapping signs, so appearance does not establish a diagnosis.