[header] How to care for a zebra danio [title] Purchase a ten-gallon tank or larger. [step] Danios are social animals and need space for themselves and their friends. The tank should come equipped with an exterior power filter, a bio-wheel, and an aquarium heater. 
[substeps] Because they are hearty, it is generally possible to keep danios without a heater. However, a heater is good for maintaining optimal conditions, especially if you plan to breed the danios.