Overview
The zebra danio is a small, torpedo-shaped fish striped from nose to tail in horizontal blue and gold lines, just like a zebra. It is fast, tireless, and always zipping around the tank, which makes a shoal of them look like a shimmering, streaking blur. Hardy and cheerful, it has been a beginner favorite for generations and tolerates a wide range of conditions.
This danio comes from the streams, ponds, and rice paddies of South Asia, mainly India and Bangladesh. Beyond the aquarium, the zebra danio, known to scientists as the zebrafish, is one of the most important animals in medical research. Its eggs are clear and develop outside the body, so scientists can watch a heart, brain, and other organs form in real time, which has taught us a great deal about how bodies grow.
| Care level | Easy |
| Adult size | 2 in (5 cm) |
| Lifespan | 3-5 years |
| Temperament | Peaceful and very active |
| Min. tank | 10 gal (38 L) |
| Temperature | 65-77 F (18-25 C) |
| pH | 6.5-7.5 |
| Diet | Flakes, small pellets, and frozen or live foods |
| Schooling | Groups of 6 or more |
A science superstar
The zebrafish is a favorite in laboratories because its see-through eggs let researchers watch organs form as the fish develops. It has even been sent into space to study how bodies handle zero gravity.
Born to swim fast
Zebra danios are almost always on the move, darting around the upper and middle levels of the tank. They are strong swimmers that enjoy a bit of current and lots of open space to zoom.
Better in a group
As schooling fish, danios need at least six friends to feel secure. In a proper shoal they are bolder, calmer, and much less likely to pester their tankmates.
Where it lives
It comes from the streams, ditches, and rice paddies of India and Bangladesh, in shallow, moving water that can range from cool to warm through the seasons.
Keeping it happy
It is one of the easiest fish to keep, handling cooler temperatures and a range of water conditions. Give it a longer tank with a secure lid, since these energetic fish can jump.
Fun facts
- Its blue-and-gold stripes give it a zebra-like look and its name.
- Scientists call it the zebrafish and use it heavily in medical research.
- Its clear eggs let researchers watch organs form as the fish grows.
- Zebrafish have been sent to space to study life in zero gravity.
- It tolerates cooler water than many tropical aquarium fish.
Frequently asked questions
Why are zebra danios used in science?
Their eggs are see-through and develop outside the body, so scientists can watch organs like the heart and brain form. This makes them incredibly useful for medical research.
Are they good for beginners?
Yes, they are one of the classic beginner fish. They are hardy, active, easy to feed, and forgiving of a wide range of water conditions.
How many should I keep together?
At least six. They are schooling fish that feel safest and behave best in a group, where they swim more calmly and show off more.
Do they need a warm tank?
Not necessarily. They handle cooler water than many tropical fish and can do well at or near room temperature, though stable clean water matters most.
