金半线脂鲤 · Golden Tetra

Overview

Hemigrammus rodwayi is often called the golden tetra, but ordinary fish are silvery gray. The striking metallic gold seen in some wild populations results from a skin response to a trematode parasite. Captive-bred fish without that exposure usually lack the same appearance.

Distribution & habitat

Its native range includes Guyana, Suriname, French Guiana, Peru, and Brazil. It inhabits slow rivers, tributaries, and floodplain lakes. Coastal floodplains support many populations, with occasional records from mildly brackish conditions; these do not make salt a routine requirement for aquarium care.

Aquarium setup

Sand, wood, roots, and a modest layer of leaves provide cover and light tannin staining. Keep illumination subdued and remove deteriorating leaves before water quality declines. A stable, densely planted aquarium or peaceful community is another suitable arrangement.

Diet & feeding

Flakes and granules are usually accepted readily. Add small live and frozen foods such as bloodworms, water fleas, and brine shrimp to maintain variety.

Behaviour & compatibility

Keep at least six, preferably ten or more. This gentle tetra does poorly against much larger or extremely boisterous competitors. Small characids, pencilfishes, dwarf cichlids, cory-type catfishes, and small loricariids can be suitable when their environmental needs match.

Sexual dimorphism

Females have a rounder abdomen. The male's anal fin has a white front margin and stronger red pigmentation.

Breeding

Prepare a very dim aquarium with soft acidic water and gentle sponge filtration. Fine plants, spawning mops, or protective mesh help separate the eggs from adults. A conditioned group can spawn, or a selected pair can be introduced in the evening after separate conditioning. Spawning often follows the next morning.

Remove parents after laying. Eggs hatch in about twenty-four to thirty-six hours, and free swimming begins another three or four days later. Feed infusoria-sized food first, followed by microworms and newly hatched brine shrimp. Keep early stages in very low light.

Notes

Gold coloration comes from guanine deposits in the skin and once led to golden individuals being described as a separate species. An ordinary silvery captive-bred fish is therefore not necessarily poorly colored through inadequate care.