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ZEBRAFISH

How Zebrafish are making a difference to heart research

What are zebrafish?

Zebrafish are small blue and silver striped tropical fish that originated from freshwater streams in Southeast Asia. While zebrafish are popular aquarium pets, they are also invaluable in research in human diseases.  

Zebrafish grow to a maximum size of around 40 millimetres. As omnivores, they feed on both small plant and animal matter in their waterways.

The zebrafish lifecycle

A female zebrafish can produce as many as 300 eggs each time she lays and can lay eggs several times each month.

A zebrafish embryo develops as much in a day compared to what a human embryo would in a month. 

This means that hundreds of zebrafish can be produced for research relatively quickly, and it is easy to keep large numbers of zebrafish in labs, with little cost.

They also grow and mature very quickly and reach full adulthood within three months. Interestingly, zebrafish only become distinctly male or female once they are two to three months old, and this can be influenced by the environment that they grow up in, such as the temperature and how many other fish are inside their home tank. 

Zebrafish Developmental Timeline | Victor Chang Cardiac Research Institute

How do zebrafish contribute to heart health research?

As zebrafish eggs are laid outside the body and are transparent, researchers can literally watch as the cells in their body grow and divide to form a fully functioning animal – something almost impossible to do in mammals. This allows scientists to detect and monitor any changes in their heart development. 

Many aspects of heart function are highly similar to humans, in some cases more comparable than heart function in small mammals such as mice or rats.

Zebrafish have the wonderful ability to self-repair heart muscle (as seen in a damaged heart). If part of their heart was removed, it could grow back within weeks. The scientists here at the Victor Chang Cardiac Research Institute are examining the fish to see if they can apply these regenerative qualities to people.

Zebrafish are currently playing a key role in the research of all 20,000 genes identified in humans, many of these relating to the heart and important causes of various heart diseases. 

Researchers are exploring the role all these genes play in human beings – what the genes do, what proteins they make, and how they all work together to interact. This important research then helps us create new medicines to tackle diseases and disorders linked to the genes.

Zebrafish are extremely useful in studying how environmental risk factors, or ‘lifestyle factors’, contribute to heart disease because researchers can tightly control the environment they live in and study many animals at the same time.

Zebrafish are also useful for testing new medicines that have the potential to treat heart diseases.

Major discoveries made with zebrafish here at the Victor Chang Cardiac Research Institute

Zebrafish have allowed our scientists to analyse large-scale data for their scientific research, to unlock the secrets to human genes, relating to the heart. Read about some of the amazing breakthroughs we've been able to make thanks to these remarkable creatures. 

Current research being undertaken

The current research undertaken by scientists with zebrafish at the Victor Chang Cardiac Research Institute include studies from:

  • Inherited Heart Disease Laboratory - who are using zebrafish to study genetic variants found in human patients with the heart muscle disease ‘dilated cardiomyopathy’ – the most common reason for heart transplantations worldwide.
  • Regulatory Systems Laboratory - uses zebrafish to study the systems biology of heart regeneration to better understand the restorative mechanisms of cells in damaged hearts invertebrates.

What does a zebrafish facility look like? 

The Victor Chang Cardiac Research Institute zebrafish facility is home to up to 70, 000 zebrafish. The zebrafish are cared for by both researchers and dedicated staff who have expertise in raising, feeding, and monitoring the health of these animals. 

Making sure all of the zebrafish are healthy and well cared for is a top priority for all who work in the facility. This means keeping a tight sleeping schedule (10 hours of sleep every day!) and a feeding schedule. 

The zebrafish facility is constantly maintained at a toasty temperature of 28.5°C, to mimic the tropical temperatures that zebrafish are originally from. 

The water that the zebrafish live in is specially filtered, and constantly refreshed so that all fish have access to fresh, clean water at all times. Facility staff also monitor water quality and temperature daily to ensure optimal fish health. 

In addition to zebrafish housing, the facility is equipped with state-of-the-art laboratory equipment for scientists to do their research. This includes things such as microscopes, high-frequency echocardiography, and electrocardiogram (ECG) to visualise and record heart function in the zebrafish.  

Get to know our scientists who work with Zebrafish