Zebrafish

Danio rerio

The Zebrafish (*Danio rerio*) is a true icon of global fishkeeping, as well as one of the most studied model organisms in genetics in the world. Characterized by its unmistakable pyjamas with horizontal dark blue and silver stripes, it is a minute cyprinid (4-5 cm / 2 inches) with inexhaustible energy. This tireless surface swimmer is virtually indestructible, tolerating impressive changes in temperature and water chemistry, making it the 'pilot fish' par excellence for absolute beginners and a permanent guest for unheated community aquariums.

Family: Danionidae
Origin: Asia (Bacino del fiume Gange in India orientale e Bangladesh)
Origin: Cosmopolitan or introducedSouth and Southeast Asia
Tank use: Used in 0 tanks

Species challenges

Temperature

18 °C - 25 °C

6.5 - 7.5

Water type

Freshwater

Tank level

Surface and middle

Adult size

5 cm

Description

Geographic Origin and Biotope: Eastern India and Bangladesh. Originally from mountain streams and fast brooks, the populations distributed in commerce are adapted to flooded plains and artificial agricultural channels.

Taxonomy and Morphology: Zebra Danio / Zebrafish (Danio rerio). The model fish of world biological research and the undisputed King of beginner aquarium keeping. Formidable hydrodynamic profile.

Social Behavior: Exuberant, unstoppable and playful. Never stays still. Must be kept in schools of 8-10 individuals; small groups cause targeted aggression among dominant individuals or against other fish.

Coloration and Sexual Dimorphism: Unmistakable livery: silvery or bright golden background crossed by marked horizontal black-blue bands extending into the fins. Females are noticeably rounder; males slender and often more golden.

Care and observations

Aquarium Setup: Ideal in 80 cm (32 inches) in length. Horizontal swimming space on the surface is the only real limit. Any layout will do. Closed tank, as they often use jumping to escape or play.

Diet and Feeding: Tireless omnivore, will eat anything. Industrial flakes, bloodworms, tubifex, microgranules. It is important not to overfeed them: their movement fools the owner into offering too much food.

Water Quality: The "invincible" fish: thrives at 18°C (64°F) as well as 25°C (77°F), withstands pH fluctuations and is the classic inhabitant of a newly set up tank. Pay attention only to temperatures over 28°C (82°F) which shorten its life (2-3 years).

Compatibility and Tankmates: Gets along with any companion who can stand its relentless hyperactivity (Barbs, robust Tetras, Botias). Never introduce with Betta splendens or slow Angelfish, they would stress them to death by stealing their food.

Aquarium Reproduction: Very easy and spontaneous ("if there is water, Danios reproduce"). In the morning they scatter hundreds of transparent eggs among the leaves, before immediately starting to eat them.

Risks and Diseases: In addition to escapes from the aquarium and spinal deformities (scoliosis) due to excessive inbreeding, it is one of the healthiest fish on the market.

Fish profile

Temperament: Estremamente pacifico, esuberante e perennemente in movimento. Nuotano instancabilmente in banco e ingaggiano innocui inseguimenti giocosi.
Diet: Onnivoro Insettivoro. Hanno la bocca rivolta verso l'alto per predare insetti in superficie. Accettano immediatamente qualsiasi cibo in scaglie o microgranulare, ma impazziscono per prede vive e galleggianti come moscerini della frutta o larve di zanzara.
Tank level: Surface and middle
Minimum group: 8
Adult size: 5 cm
Minimum tank: 80 L
GH: 5 dGH - 15 dGH
KH: n/a
TDS: n/a
Conductivity: n/a
Sex ratio: Gruppi misti. Il maschio è più snello e con riflessi dorati tra le strisce blu; la femmina ha un ventre decisamente più pronunciato e rotondo, con sfumature argentate.
Feeding frequency: 1-2 volte al giorno. Veloci e ingordi, spesso rubano il cibo ai pesci più lenti.
Bioload: Basso
Flow: Corrente da Moderata a Forte (eccellenti nuotatori controcorrente, amano il flusso dell'uscita del filtro)
Jump risk: Covered tank required
Reproduction: Egg-scatterers estremi. Una femmina gonfia inseguita da più maschi disperderà centinaia di uova non adesive sul fondo in un solo mattino. Essendo spietati divoratori delle loro stesse uova, la riproduzione va condotta in una vasca separata con rete sul fondo o strato di biglie di vetro.
Compatibility: Pesce di comunità formidabile, ma la sua iperattività può stressare compagni timidi, lenti o pesci con pinne a velo. Ottimi con Corydoras, Tetras veloci, Barbi pacifici e Loricaridi.

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.