克氏斑马鱼 · Blue Danio

Overview

Color in Danio kerri varies geographically: northern populations tend toward powder blue, while southern ones can be more yellow-green. Pinkish-yellow flank lines complete the appearance. These differences should not automatically be interpreted as male and female coloration.

Distribution & habitat

Originally described from Ko Yao Yai in southwestern Thailand, it has additional records from nearby islands, the southern Thai mainland, and Langkawi. Clear forest streams and small rivers over stones and gravel are typical. Aquatic plants are often scarce, but banks are densely vegetated and submerged surfaces carry biofilm.

Aquarium setup

Use a planted aquarium with dark substrate or a stream arrangement of gravel, rounded rocks, and wood. Moderate circulation is appropriate; retain calm areas rather than creating relentless current. Attached ferns and anubias can provide cover. Ample swimming length and a tightly secured lid are essential, since fish can escape through small gaps.

Diet & feeding

Insect remains dominate examinations of wild stomachs. Minor plant and detritus traces may originate in prey guts. Captive feeding is straightforward: a quality dry staple should be accompanied by regular small frozen or live meals.

Behaviour & compatibility

Eight to ten or more fish provide an effective social group. Their presence encourages confidence and stronger male display colors. Many peaceful, suitably sized community species can be considered once environmental requirements are matched.

Sexual dimorphism

Adult females usually grow slightly larger, carry a rounder belly, and show somewhat subdued colors. Reproductive condition makes the differences easier to see.

Breeding

Eggs are dispersed and receive no parental care. Dense planting may shelter a few offspring without intervention. A separate spawning tank with moss, mops, or an egg grid improves control. Use slightly acidic to neutral water toward the warm end of the normal range, then introduce one or two conditioned pairs.

Gradual cooler-water additions or a substantial evening water change, accompanied by small live-food meals, can stimulate laying. Remove adults as soon as eggs are seen and protect the young with mature sponge filtration. Hatching normally takes about one to one and a half days. Once swimming freely a few days later, fry can take brine-shrimp nauplii or comparable food.

Notes

Other blue danios have been confused with this species. Assess the flank markings and provenance rather than relying on a retailer's color-based label.