The danios found in the aquarium hobby are mostly small fish, but with a few notable exceptions. They are very active fish, chasing back and forth with frenetic energy for most of their lives. Being mainly surface swimmers they are useful to fill that upper strata of water in the aquarium that might otherwise be devoid of fishy activity. Keeping danios is simple, and breeding them is also an easy task.
Giant danios (devario aequipinnatus) are one of those few larger exceptions mentioned above, and can grow to be about 4 inches/10 cms. Long. The colouring is quite variable from strain to strain now that they are mostly domestically bred. Cover the aquarium well, as these fish are agile and will jump.
The Zebra Danio (danio rerio) is one of the favourites in the hobby and has been around just about as long as from when tropical fishkeeping began. The steel-blue stripes against the shining streamlined silver body and fins, are set off beautifully. This hardy fish may be kept in the indoor unheated aquarium.