Hi, Page.
Interestingly, even though they are members of the kingfisher family, Kookaburras aren't really fish eaters...
"Kookaburras are almost exclusively carnivorous, eating mice, snakes, insects, small reptiles, and the young of other birds; unlike many other kingfishers, they rarely eat fish, although they have been known to take goldfish from garden ponds. In zoos they are usually fed food for birds of prey."
Source: https://en.wikipedia.org/wiki/Kookaburra#Behaviour