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What is a Zebrafish?

A zebrafish is a small, tropical freshwater fish, notable for its striking stripes and remarkable regenerative abilities. Scientists value it for genetic research due to its transparent embryos and genetic similarity to humans. Understanding zebrafish can unlock insights into human development and disease. How might these tiny swimmers influence future medical breakthroughs? Join us to uncover their potential impact.
Anna T.
Anna T.

Zebrafish are a type of tropical fish native to the freshwater streams of India and Myanmar. They tend to be very small fish, with most not growing to be longer than 1.5 inches long (3.8 cm). Some types have black and white zebra-like stripes running horizontally across their bodies, while other species may be pink or blue in color with noticeable spots. There are also differences in fin size between various species, but the type most commonly seen in the wild has short fins. Many people like to use these fish in their home aquariums because of their small size and bright appearance.

It is usually possible to tell the difference between a male and female zebrafish by looking at the fish's underside. Males typically have gold coloring on their bellies, and females normally do not. The males male also be longer and slimmer. Female zebrafish lay eggs on a daily basis, so they will normally appear to be rounder than the males. Another way to tell the difference between the sexes of zebrafish is to watch the males chase the females at breeding time, which happens early in the morning almost every day.

Veterinarian with a puppy
Veterinarian with a puppy

Zebrafish are somewhat unique because of the development of their embryos. The embryo develops on the outside of the mother fish, and it is also transparent. This makes the zebrafish very interesting to scientists because they can actually study the young as it develops in real time. Scientists are trying to use this to their advantage because baby zebrafish develop in much the same way as baby humans. This means that a scientist can manipulate the cells as the fish develops to see what effect this manipulation has on development, which may ultimately help scientists determine what causes certain birth defects in humans.

In most cases, zebrafish are a good choice for someone who is just getting started with keeping aquarium fish. They tend to be very easy to take care of and are relatively inexpensive. These fish may also be fun to watch because they have a playful nature. Keeping clean water in the fish tank at all times is important to their survival, but the water doesn't have to be fresh. They do well in older water as long as it is kept clean of old food debris and dead eggs, but it may need to be changed if it starts to look hazy.

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Discussion Comments


@googie98: The research done on the zebrafish is fascinating, to say the least. Since the eggs are clear and develop outside the mother’s body, scientists can watch the zebrafish egg grow into a new fish under a microscope.

The scientists study the cells dividing and forming different parts of the baby fish’s body. They saw that in the development span of 2-4 days, some form to create they eyes; others form to create the liver, heart, skin, fins, etc.

This important research has helped scientists in discovering the causes of birth defects in human children.


@googie98: Yes, that is true. Back in the 70’s, a scientist by the name of Dr. George Streisinger from the University of Oregon determined that the zebrafish was a great model to study vertebrate genetics and development.

His research led to more understanding of not only fish, but all vertebrates, including people, and the fact that we start developing from the moment that a sperm fertilizes an egg.


I have heard that there is zebrafish research being done. Is that true? If so, what is the research about?

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      Veterinarian with a puppy