Minimum Tank Size: 5 Gallon (10 Gallon Recommended)
Care Level: Very Easy
Water Conditions: pH 6.5-7.2 and Soft to Medium Hard
Temperature: 65-77 °F (18-25 °C)
Maximum Size: 2.5 inches (6 cm)
The zebra danio (Danio rerio) is one of the most iconic fish in the aquarium hobby, and many people have even owned this interesting fish at some point in their lives.
In addition to their attractive coloring and stripes, the zebra danio has a well founded reputation for being a playful and curious fish and makes an excellent addition to almost any community fish tank.
They were originally found in the streams of India, Pakistan and several bordering countries, but have since spread as an invasive species in several US states. In the wild, they can be found in everything from fast flowing streams, to stagnant rice fields. But their preferred habitat is usually water with a moderate amount of current.
While many of the original zebra danios in the fish trade were wild-caught, nearly all of the ones available now have been breed in captivity in fish farms. Because of this, they are adapted to a wide variety of water types, and if given enough time to adapt, will thrive in most home aquariums.
Zebra danios stay relatively small in the home aquarium, and most will only grow to around 2 inches (5cm) in length. With that being said, some have been known to reach sizes of 2.5 inches (6cm) and there have been reports of even larger ones. They also tend to be a short-lived fish, and most will only live two to three years in a home aquarium, though it’s not unheard of for some to live as long as four or even five years.
People who has ever kept zebra danios, will often swear that these fish have a touch of ADHD. They are constantly zooming around their aquarium, and because of this, should be provided with the largest aquarium possible – or at least the largest one that you can fit into your budget.
While they can survive in a 10 gallon (37 litre) aquarium, they tend to only really thrive in larger aquarium. Since they are a schooling fish, they need to be kept in groups of at least five, and five danios can quickly become cramped in a 10 gallon (37 litre) aquarium. Any zebra danios that aren’t kept in a school, will often become stressed and may begin to display aggressive behavior towards other fish in the aquarium. However, once their numbers are brought up so that there are at last five of them, most of the aggressive behavior will disappear.
Zebra danios are not a demanding fish when it comes to filtration and any HOB (hang-on-back) filter or sponge filter will usually suffice. HOB filters are usually the best choice, since they not only provide excellent filtration, but they also keep the danios occupied for hours playing in the filter’s current, or making vain attempts to jump up into the filter discharge. (You can read the Seymour Fish HOB filter reviews here.)
It should really come as no surprise, that a fish that enjoys jumping up into the filter outflow, also enjoys trying to jump out of their fish tank. So to avoid any untimely fish deaths, any tanks containing zebra danios should always be covered. Barring a cover, the water level should be lowered to make it more difficult for the fish to jump out.
Zebra danios are not what you would call fussy eaters, and will eat nearly anything that you offer them. In the wild they tend to mainly feed on small crustaceans, insects, worms and algae. This diet should be reproduced as closely as possible in the home aquarium, and this can be accomplished through feeding them a high quality flake food, and occasional feedings of live or frozen foods. I personally use New Life Spectrum Small Fish, and the fish seem to love it.
But when it comes to live foods, there are few fish that enjoy regular feedings of live food more than zebra danios. They they will greedily accept wingless fruit flies, blackworms, bloodworms, brine shrimp and daphnia. If you can’t provide live foods, then they can be provided with frozen bloodworms, daphnia, blackworms and brine shrimp.
The zebra danio has a reputation as one of the easiest fish to breed in the hobby, and they can be a great way for a beginner to experience breeding fish for the first time.
Like many other fish, zebra danios first have to be conditioned to trigger their mating behavior. The first step in breeding them should always be to separate the sexes into their own tanks. The females can be identified by their plump bodies and rounded bellies, while the males tend to have more streamlined and narrow bodies.
After the sexes have been placed in separate tanks, they should be fed live food for at least a week. If live food isn’t available, a high quality frozen food can be substituted. Over the course of a week, the female will begin to plump up visibly, as they begin to swell with eggs.
While the fish are being conditioned, a special breeding tank should be set up. It should be fully cycled, and should only be filled with a few inches of treated water, with river rocks or marbles lining the bottom. The rocks or marbles are integral to the breeding process, since it allows the eggs to fall between them – and out of the reach of the hungry parents.
After the fish have finished being conditioned, they can be introduced into the breeding tank, and spawning will normally occur the next day. After spawning, the females will be noticeably thinner, and if they haven’t spawned after a day, they should be moved back into their separate tanks to begin the process over again.
When it comes to parental care, zebra danios are not exactly the model parents of the fish world. They should be removed immediately from the breeding tank after they have spawned, as they are more than happy to eat every egg that they can find. This is why it’s so important to use the marble setup, since it’s unlikely any eggs will survive without it.
Within 48 hours, the eggs will begin to hatch, and the newborn fry can be fed with infusoria, baby brine shrimp or any of the commercial fry foods (I personally recommend New Life Spectrum Small Fry Starter Formula or Hikari First Bites).While it takes a bit more effort and planning, most aquarists prefer to use newly hatched brine shrimp. You can find a brine shrimp hatchery at Amazon.com here.