Fish of the Week: Zebrafish

Zebrafish are very hardy and are great for beginner aquarists.   They are adaptable to a wide range of environmental conditions and occupy all regions of the tank.  They are not shy and do not startle easily.  Zebrafish are prolific breeders in captivity but will eat their own eggs if given the chance.  Since they are small and can tolerate a wide range of temperatures, zebrafish are good candidates for small aquaponic systems or outdoor container ponds.


Family: Cyprinidae
Genus: Danio
Species: rerio

Natural History

Zebrafish are natively found in vegetated shallow bodies of water ranging from Nepal and the lower Himalayas through Pakistan and lower India.  Zebrafish are omnivorous, eating both vegetation and small invertebrates.


Description: Slender, silver body with blue horizontal stripes.  Females have a distinct football shape body type and pronounced silver belly.  Males are more torpedo shaped and exhibit pink and golden pigment along the margins of the anal and caudal fin when sexually mature.

Size: 2-2 ½ inches

Temperature: 64-80*F

pH: 6.5-8.0

Habitat: Provide plenty of open swimming space with ample vegetation, gravel bottom

Minimum tank size: 2.5 gallons


Zebrafish will accept all types of small dry, frozen, and live foods.  Zebrafish actively feed at the surface and could potentially outcompete slower tank mates.


Zebrafish are a good community fish or themed shallow running water tanks.  Zebrafish can be territorial if kept singly or in pairs.  Zebrafish form small dominance hierarchies in their shoals, so having at least 6 fish will help disperse their aggression. Zebrafish should not be kept with large, slow moving fish (angelfish) or fish with long flowing fins (guppies or betas) as they might charge and nip at fins.  It would be best to keep zebrafish with other small quick swimming fish such as barbs, tetras, and other danios.

Interesting Notes…

Due to their ease of care, small size, and reproductive success zebrafish are a very popular model organism in biomedical research. Since they share many of the same genes as humans they are an ideal model for studying disease.  Many of the glofish that you see in aquarium stores are results of research in genetic modification.  These are zebrafish that were genetically modified by injecting zebrafish eggs with a jellyfish gene which produce fluorescent proteins when activated.  Since the gene is inheritable, most of the Glofish you see today are captive bred.

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