The zebrafish life cycle

Zebrafish are an important research organism at Auckland University. Check out the fry, the adults and the system in which they live.

Transcript

Peter Cattin (Auckland University): After fertilisation, they spend the first week in a petri dish in the incubator in the next room at 28 degrees. From the incubator, at day 6 or 7 post-fertilisation, they go into our nursery. But if the conditions during that first 14 days are not of a high standard, they will all fall over on day 14 - you can set your watch by it. So it’s very important to get them through that first 14 days. Three weeks later they come back into here.

These ones here are already about 6 weeks of age. These ones here are probably about two months. In these tanks labelled ‘fry’, we’ve got several of them through here, these are only about a month old. They’re about 15 mm long.

We keep them at relatively high densities in here until we’ve got an experiment requiring eggs. At that point we will reduce the numbers of fish per tank, or the density of fish, so that we allow the fish to grow. Fish exhibit what is known as an indeterminate growth, where they will grow to fill the space. They can remain at that size, and even at that age if we then reduce the densities they will still grow to a full adult size.

So one of the main purposes of the husbandry side of things here is to ensure that the fish are well cared for so that they remain healthy and reproduce well, have high fecundity, high numbers of eggs. Because this is what we are working with. We can’t have poor conditions for our fish to live in.