Zebra fish Danio

Common name: Zebra danio, Zebra fish
Scientific name: Danio rerio
Family: Cyprinidae
In nature: Eastern India
Mature fish size: 6 cm / 2 inches
Social: peaceful, compatible to most tropical fish
Swimming in the aquarium: top and middle levels
Feeding: eats most foods, dried or live
Breeding: oviparous – female lays eggs that start development after they are fertilized externally by the male
Water Temperature: 18-24 C / 64-74 F
Water pH: 6.5 – 7.0
Water Hardness: 5-12 dGH

Description

Zebras are very active fish, and easily recognized by their 5 horizontal stripes that resemble pijamas :). They have blue horizontal stripes from gills to tail, over the silver base color of the body (males have gold instead of silver). They have two pairs of barbels. Females are a bit larger than the males and more full-bodied when they are mature and carry eggs. Males are streamlined and slim. Here is a couple, the bigger female being followed by the slim male:

Behavior

Zebra Danio is a small fish, and because of its peaceful nature and hardiness, is recommended for beginners. They adapt to a wide range of water conditions. They need open swimming space, being sporty fish that you rarely see still! :) Fin nipping on other fish occurs when they feel lonely, so it’s a good idea to keep 6 or more zebras in the same tank.

Sometimes, zebra males will occasionally simulate fight, straightening their pectoral fins and staring at eachother! After a while they forget it and go on with their crazy racing in the tank. You will have a lot of fun with their playfulness. Don’t forget to cover your tank since zebras are known for their skills in jumping out of the tank for freedom.

Bleeding of the gills can happen if the fish are exposed to ammonia, which is why it might not be a good idea to use them as starter fish in the nitrogen cycle, or if you do, measure the water chemistry often and act to keep them safe.

It is worth knowing that zebra danio is often used in scientific research.

Varieties
Although I prefer the original natural “version” of the fish, there are several varieties created by selective breeding:
- leopard zebra (it has dots instead of stripes… kinda funny and nice variety actually)
- albino zebra
- veil tail zebra
- long fins zebra

Feeding
Zebras are omnivorous, and although like every fish they love live foods, they will accept dried/frozen food very well. Their mouth is directed upwards, so they prefer feeding from the top of the water. They will try to eat anything that fits into their mouth :).

Mouth directed upwards:

Breeding
Probably the easiest to breed from the oviparous category of tropical fish, zebras are very prolific. I was impressed to find out that zebras are loyal to their mate and they remain together for life, and rarely get another pair, even if one mate dies. I didn’t expect this from such a small crazy common fish :).

They eat their eggs so a grid is required at the bottom of the tank so that the eggs fall below it and escape the parents. Rising the regular temperature a bit will trigger spawning, it this should be done during dawn, because this is when they usually lay eggs. A female can produce up to 500 eggs. The parents must be removed after the eggs are fertilized, because they will also eat their young. After 2 days, you’ll notice the tiny fries. They need very finely crushed dry food and infusoria. Egg yolk might be added too, but in moderation since it spoils the water quality and cleaning the fry tank is very difficult, since they are extremely small and easily absorbed with the water.

Fun facts
Zebra’s face is always grumpy! Zebra fish looks like one of my grumpy friends. See?