What Do I Do After Danio Eggs Hatch?

Various species of danio grace the aquarium hobby, including the zebra, leopard and blue danios. The danio family will breed in captivity much more readily than most egg-laying fish. However, baby danios or fry hatch at a very tiny size and need some special care to survive to adulthood.

  1. Post-Hatch

    • Believe it or not, you want to do very little for baby danios for the first several days. All you want to do is the crucial act of removing the parents, if you haven't done so before the eggs hatch. From the time between the hatching until the fry start swimming, do not feed them. During this time, the fry live off their yolk sacs, and anything you try to feed them will just rot and foul the water. The exact length of time varies by the species of danios and the water conditions but can range from two to four days. Do not worry about water changes until you start feeding the fry.

    Feeding

    • The most difficult thing about raising danio fry is feeding them. The fry have trouble accepting common first foods like ground-up fish flakes or baby brine shrimp. However, they will readily eat infusoria. Infusoria consists of tiny creatures including protozoa, single-cell algae, Euglena, Paramecia and other micro-organisms. The exact composition can vary based on the starter culture and the nutrients you provide. You can purchase infusoria cultures online, either as cultures of individual organisms like Euglena or Paramecium or as "green water," a cocktail of various microorganisms.

    Culturing Infusoria

    • You can grow infusoria a number of ways. Plan ahead, since it take three to five days to culture enough of them. To culture, wash and shred some spinach or lettuce and add it to a mason jar full of distilled or aquarium water. Inoculate the water with your starter culture. You will want to prepare this in a ventilated area, since an infusoria culture can smell bad. The water will turn greenish as infusoria reproduces in the water.

    Daily Chores

    • To feed the fry, siphon a few drops of greenish water from the bottom of the infusoria culture into the aquarium. Add a few drops two to three times a day. You also need to drain and replace about 10 percent of the aquarium water daily to keep it clean for the fry. You also need to stagger your infusoria cultures since they tend to go bad after two to three weeks. Start a new culture weekly to make sure you have plenty of food for the baby fish. Once the fry get large enough, you can switch to ground-up fish flakes. The exact time frame depends on the species of danios and the water temperature. Usually, by the time fish grow to three-quarters of an inch, you can switch to ground-up flakes. However, you may need to experiment. Siphon off the uneaten powder if the fish ignore it.