The Tauranga-based KD Kirkby Trust, long a benefactor of Cure Kids, has made a $45,000 grant to provide the microscope, bringing the trust's support for medical research to almost $150,000.
Cure Kids regional manager Josie Spillane said the charity, which aimed to improve the health of young New Zealanders through research, was indebted to Guardian Trust and the KD Kirkby trustees for their foresight in supporting Otago University research into children's life-threatening illnesses.
University pathology head Prof Ian Morison said zebrafish had proved an "amazing" model for human development.
This included blood development and "even more importantly, childhood leukaemia", the most common form of cancer in children.
"Extraordinarily, if you take the abnormal gene that occurs in nearly a quarter of acute lymphoblastic leukaemia (ALL) and put it in zebrafish, they will get leukaemia."
This abnormal gene was rather common, perhaps 1% of all children at birth having it, but only about 1% of those went on to develop leukaemia years later.
Similarly, only about 3% of the zebrafish with this gene contracted ALL after eight to 12 months.
"The parallels are striking and they provide hope that we will be able to identify other factors that contribute to the development of leukaemia," he said.
The high-tech microscope turned the zebrafish facility into a "world-class amenity".
"If our finding is confirmed in the fish, our studies will point to new pathways and targets for therapy in childhood leukaemia."
Prof Stephen Robertson, the Cure Kids Child Health chairman, at Otago University, said the microscope funding had made a "phenomenal" contribution to the zebrafish facility.
Discovering a gene that went awry in disease was often only the first step towards understanding a condition.
The microscope enabled researchers to study living fish, and to watch the gene "play out its function" during animal development, with "state of the art precision", he said.
