Question 1

Why is water quality so critical for zebrafish health in the laboratory?

Accepted Answer

Optimal water quality directly promotes fish health and experimental reproducibility. Tap water is toxic to zebrafish due to chlorine and contaminants, so aquarium water must be purified through reverse osmosis systems. Salts and pH buffers are then added back to recreate the natural fresh water conditions zebrafish require, ensuring both animal welfare and reliable experimental outcomes.

Question 2

How do fish facilities manage water waste while maintaining zebrafish populations?

Accepted Answer

Fish facilities use recirculation systems to minimize water use and manage waste buildup from many fish in limited water volumes. Dirty water is filtered and sterilized by UV treatment before flowing back into the system. Regular tank cleaning removes algae and solid waste. An overflow port with a baffle allows dirty water to exit while preventing fish escape, maintaining stable water levels.

Question 3

What environmental conditions must be maintained in a zebrafish facility?

Accepted Answer

Temperature is maintained near 28°C (80°F) to support zebrafish physiology. Light cycles are controlled with 14 hours of light and 10 hours of darkness to maintain the animals' circadian rhythm. Specialized tanks with covers reduce evaporation and prevent escape. These controlled conditions are essential for fish health, proper development, and consistent experimental results.

Question 4

What do zebrafish eat in the laboratory, and how often are they fed?

Accepted Answer

Larval and juvenile zebrafish thrive on live microorganisms like paramecia, while adult fish are fed commercially available powders and brine shrimp. Brine shrimp eggs are decapsulated using bleach, washed, and hatched in aerated towers with salt water for about one day. Fish are generally fed 2-3 times daily, alternating live and dry feed, with water flow turned off during feeding to prevent food loss.

Question 5

How are different zebrafish strains tracked and maintained in laboratory facilities?

Accepted Answer

Fish with similar genetic backgrounds are kept together in labeled tanks containing thorough identifying information, including genotype and date of birth. Zebrafish fertility declines after the first year, so stocks are replenished yearly. Genetic diversity is maintained through outcrosses of unrelated fish. Progeny bearing desired genetic modifications are identified by fluorophore expression or genotyping using tail fin DNA samples.

Question 6

How is genotyping performed to identify specific genetic modifications in zebrafish?

Accepted Answer

Fish are first anesthetized in tricaine, then a small piece of tail fin is removed as a DNA source. DNA is isolated from the tail sample and analyzed using PCR to identify specific genetic sequences. Each fish is kept in its own labeled tank during genotyping. This method allows researchers to identify progeny carrying desired transgenes or mutations for stock maintenance and experimental studies.

Question 7

How can researchers manipulate the zebrafish environment to study specific biological processes?

Accepted Answer

Environmental conditions can be modified to model disease or study behavior. Reduced water temperature combined with pancreatic toxin treatment creates a diabetes model showing kidney damage, eye damage, and reduced tail fin regeneration. Altered light conditions can ablate retinal cells, allowing study of tissue repair. Video tracking systems analyze swimming behavior changes in response to drugs, supporting neuroscience research and drug discovery applications.

Zebrafish Maintenance and Husbandry - Assessment Quiz