Zebrafish as a Model

It was determined in the late 70s that the zebrafish is an excellent model for studying vertebrate development and genetics. The eggs are clear and develop outside of the mother's body, allowing scientists to watch it grow into a newly-formed fish under a microscope. The cells divide and form different parts of the baby fish's body. Within days, cells form the eyes, heart, liver, stomach, skin, fins, etc. until the fish is complete.


Scientists will occasionally move a cell to another spot to see if it will still form the same part of the body as it is known to do in other embryos--or if it will do something different. Occasionally a cell is removed or destroyed to see what the result is to the fish once it has developed. This is how scientists discover the causes of birth defects in human children, and ways to prevent them by understanding why they happen and what original cells were involved.



This zebrafish is being studied as part of 2010 scoliosis research conducted by Drs. Henry Tomasiewicz and Xue Cheng-Lui. The complex curvature of the spine is a result of exposure to toxins.

Aquatic Animal Models Facility Core

Core Director: Henry Tomasiewicz, PhD

The Aquatic Animal Models Facility Core (AAMF) is a research support service for numerous Center scientists and, as such, provides experimental animal research opportunities that otherwise would not be available to them. During its 30 years of existence, the AAMF has provided expert assistance in the use of aquatic organisms in biomedical research to scientists both familiar and unfamiliar with aquatic organisms. This is exhibited with the flexibility to adapt and adjust to meet the changing needs of individual Center investigators—while maintaining high standards of animal care. In the past, Center investigators used adult trout, fathead minnows, goldfish, sunfish and Xenopus laevis in their toxicological experiments, each requiring a different set of conditions (water temperature, light cycle and aquaria size) for optimum growth.

The Aquatic Animal Models Facility is a 3,000 square foot facility within the WATER Institute. The Institute houses research programs ranging from the physical and chemical studies to ecological studies of Lake Michigan to human health-related work. The WATER Institute is located on the inner harbor of Lake Michigan, a 15-minute drive to the University’s main campus and similar distance from the Children’s Research Institute. The AAMF is part of an AALAC-accredited set of animal facilities and provides expert care for a variety of aquatic animals, with an emphasis on zebrafish.

Its operation is guided by these goals:

  • To continue offering high quality, flexible services to Center investigators
  • To enhance the knowledge and skills of the technical staff in support of toxicological studies with zebrafish
  • To support investigator and student understanding and use of the facility
  • To continue to improve the facility operation and service
  • To improve an excellent record of zebrafish husbandry through further technical advances
  • To support Community Outreach and Education projects utilizing aquatic organisms
The facility core consists of three separate but related areas:

Each facility is staffed by an expert in the area and is equipped with state-of-the-art instrumentation and infrastructure. We welcome your use of the facilities and are ready to provide assistance in all phases of experimentation with aquatic organisms.

The Neurobehaviorial Toxicology lab offers a unique array of instrumentation designed to determine the effects of environmental toxicants on the nervous system of aquatic animal via observable changes in their behavior.

The Aquatic Models Molecular Techniques Facility is equipped with modern molecular biology equipment used for assessing the affects of environmental toxicants on gene expression. An experienced staff is adept in molecular biological methods and, particularly, in designing vectors for creating transgenic fish.

In 2000, with the hiring of Dr. Michael Carvan, zebrafish became the focus of the Center and the AAMF was reconfigured to handle thousands of small aquaria used to house zebrafish. Presently, the facility:

  • Can house 15-20,000 zebrafish in the main area of the facility.
  • Has several smaller rooms reconfigured to handle smaller, but substantial number of embryonic and juvenile trout, and fathead minnows for use in toxicological experiments.
  • Has a toxic agent exposure room designed to handle simultaneously three different aquatic species, each requiring different water conditions for investigators using highly-toxic environmental chemicals (e.g., TCDD, methylmercury and chlorpyrifos).
  • Offers a computer software program to track the life history of all of the zebrafish in the facility.
  • Has standard operating procedures for all phases of animal care and experimentation.
  • Offers daily zebrafish egg production of 300 per female with an embryo survival rate of 85-90%.
    • Both are among the best reported at any facility and are necessary for the type of research carried out in the Center.
    • Such studies commonly involves early life stage studies, requiring abundant embryo production and high control survival so that the sublethal effects of toxic chemicals can be observed and quantified.

Dr. Henry Tomasiewicz has extensive experience in the culture and experimental handling of zebrafish and other fish species. Contact Dr. Tomasiewicz at (414) 382-1746 or henryt@uwm.edu.

The day-to-day activities of the AAMF, including overseeing a staff of trained students and employees, are managed by Kris Kosteretz. Contact Mr. Kosteretz at (414) 382-1735 or krisk@uwm.edu.

Those who use the facility regularly meet monthly to discuss issues that arise with respect to the AAMF, as well as to contribute to the writing of new standard operating procedures. Like all animal research, it must meet the requirements of the UW-Milwaukee Institutional Animal Care and Use Committee.