Caring for Zebra Danios
(Danio rerio, formerly Brachydanio rerio)

by Peter McKane
of England. From his website www.helpthefish.org
Aquarticles.com

Caring for such a vibrant and active fish is not as easy as people may lead you to believe. Even though the zebra danio is a common fish, regularly found in tropical community tanks world wide, they do require something of a caring touch to make sure that they are both happy and healthy. Most people are not aware that the zebra danios' hyperactivity is actually a sign that they are slightly aggressive. They are schooling fish, and if they are not kept in sufficient numbers, then their schooling behavior will mix with their aggression and lead to fin-nipping and even attack on tank mates. A good school size for zebra danios is a minimum of five fish, with a preference for nine or ten. If you watch a well housed school of danios, you will quickly see that the males will occasionally display fight. It is this behavior that translates to aggression and fin nipping when they are improperly housed. Typically, the display fights involve nothing more than two male danios staring at each other and straightening their pectoral fins. It will last for about twenty seconds until one of the danios gets scared off, forgets what it is doing or simply gets bored.

If you have an open topped aquarium then before you get these fish you need to get a hood. Zebra danios are notorious jumpers, and will make frequent bids for freedom by jumping through whatever gap they can get through. Do not be surprised to find that if your hood has large gaps for cables and air hoses that your danios have miraculously managed to get through. There are few fish more tenacious when it comes to escaping their tank to the daylight in the sky than the zebra danio. Taping over these holes is the best thing to do, or plugging them with sponges also works.

Feeding a zebra danio is incredibly easy. They will try to eat practically anything floating and mouth-sized in your tank. They are also likely to pick the snails from your window, but they will never eat them. They will eat flake foods from the surface greedily, and their diet should be supplemented with live foods like bloodworms, white mosquito larvae, water fleas and artemia. Frozen foods will also not be a problem, but freeze dried foods will lack the sufficient nutrition that such an active fish will require.

Zebra danios, while being fairly hardy fish, are prone to have bleeding or ulceration of the gills if their aquarium contains even slight traces of ammonia. This is easily cured with regular water changes, but if it is persistent then it can be a sign that the water you use in re-filling your tank may contain traces of ammonia, iron or phosphates. A good test kit will be required to prove this, and can usually be quickly rectified with ammonia absorbent stones or water conditioner. Both of these things are readily available at your local fish store. If such a problem persists, then you should move the affected fish to a hospital tank and treat with vitamin enriched flake foods and an anti bacterial medication to ensure that the wounded areas do not become infected.

When a zebra danio is nearing the end of its typically two year lifespan, there will be a moderate to severe curvature of the spine. This is occasionally confused with fish tuberculosis, a disease that can be passed on to humans. If your fish are young and exhibit this particular trait, then you should take the highest precaution in diagnosing the cause. Remember though that stress will often be responsible for the reduction of the life of a fish, and that a zebra danio that experienced a high level of stress as an immature fish may have its life expectance reduced to no more than nine months. Zebra danios are not prone to any particular disease, and because of their active nature they are seldom affected by ich, due to the fact that they will brush off the fungus in their everyday activity of passing by stones or plants in your tank. One thing to look out for is gill flukes. If you spot your zebra danios rubbing themselves along the substrate of your tank, then you will probably need to medicate the tank with an anti parasitic medication.

Knowing that zebra danios need to be kept in schools, preferably away from fish with fancy tails or fins, you can expect to have absolutely not problem with the fish in a community tank. Their nature and liveliness is guaranteed to bring a spark of life into your community, and their playfulness will surely keep you highly entertained. Enjoy their vitality!