Zebrafish (Danio rerio)
Tropical freshwater fish belong to the order of Cypriniformes. Of Himalayan origin, they are becoming increasingly popular as research models.
The Comparative Pathology Lab is happy to assist you in both diagnosing sick fish or setting up a sentinel program to ensure the health of your fish. Listed below are the types of things you might see in sick fish as well as a brief discussion of our sentinel program for zebrafish.
Health Monitoring and DiseaseDiseased fish often exhibit similar clinical signs for different diseases. Fish should be observed daily for abnormal behavior. Fish that appear abnormal should be identified and separated out into their own container (Always wear gloves when handling fish or their water). There are two broad categories of clinical signs; changes in behavior and changes in appearance.
Signs of Disease in Zebrafish
Poster provided curtesy of the FishVet Group
Changes in Behavior:
- Loss of appetite
- Lethargic swimming
- Flashing and thrashing
- Equilibrium disturbances
- Swimming in isolation
- Congregating at the top or bottom of the tank
- Clamped fins
- Changes in respiratory rate
- Gasping at surface of water
- Opercular flaring
Changes in appearance:
- Skin changes (hemorrhage, ulceration or masses)
- Scale loss
- Fin damage
- Changes in color (loss or gain of pigment in an area or over entire body)
- Ascites, coelomic distention (swelling)/ dropsy ("pinecone" appearance with raised scales)
- Exophthalmia "popeye" or endophthalmia "sunken eyes"
- Skeletal or other deformities, i.e. curved backs
- Poor body condition
Diseases of Zebrafish:
RARC Comparative Pathology Lab Sentinel and Health Monitoring Program
Sentinel fish may be submitted quarterly, semi-annually or annually depending on consultation with your clinical veterinarian and whether or not you have a closed colony or are bringing in new fish. While PCR panels (IDEXX; Charles River) can be done on new fish to ensure you are not bringing in any diseases, fish held here at the UW rarely need such panels done on a regular basis. Our program involves the submission of 5-10 live fish (We ask that you submit a mix of healthy appearing and poor doing fish). We will euthanize the fish and divide them into those we will send for culture to a lab specializing in culturing aquatic species and those on which we will do gross necropsies and histopathology. The final report will list any infecting organisms as well as all lesions.
Ask the Vet
Zebrafish Working Group
Zebrafish users interested in joining the Zebrafish working group, please contact Marc Wolman
Zebrafish may have a preference for colors that could increase the average number of eggs produced and the percentage of eggs that hatch. Studies have shown zebrafish show a preference for red and green marbles, but recently a brief study (Patty Oden, UAB) started to look at the color of marbles for breeding performance. In this study, red and clear marbles produced both a higher average number of eggs and a greater percentage of those eggs hatching. Not everyone uses marbles for breeding but that doesn't mean you can't use colors to your advantage.
Do you want to learn more about this?
Contact the vet: Dr. Pierce Sullivan, firstname.lastname@example.org
- Z-Fin The Zebrafish Information Network
- Zebrafish International Resource Center
- Zebrafish reference genome sequence
- Why Use Zebrafish to Study Human disease
- The RARC Training group can help train people on some zebrafish research procedures, email: email@example.com
- RARC also provides access to the AALAS Learning Library's online courses Working with Laboratory Zebrafish, and Aquatic Animal Husbandry and Management email: firstname.lastname@example.org or see RARC website at https://www.rarc.wisc.edu/training/course/zebrafish
- Color Preferences of Zebrafish: Can they affect mating behavior and reproductive performance? Patty Oden
- The Laboratory Fish, ed. Gary Ostrander Academic Press 2000