The Danios are a bigger family of fish. They come in many different versions. Some of the most popular ones are these: Zebra Danios, Pearl Danios and Queen Danios. Now, let’s take a look at the Zebra Danios, more closely: You need at least a 10-gallon tank for housing Zebra Danios. They grow up to 2 inches long, so they’re not the biggest among fresh water breeds. Being so small and peaceful, makes them great choices for community aquariums. Differently from many other species in this article, the Zebra Danios will thrive in colder waters, just as well as warm ones. Most Danios need a water that’s between 64- and 75-degrees Fahrenheit. So, you don’t need a water heater, to keep Danios in your tank. But a great water filter is a must. They need a crystal clean water, to thrive in. Make sure you buy a cleaner that does a good job at this.