There is no official estimate of the amount of fishes used in research. In the US, the Animal Welfare Act, which provides some protections to animals used in research, does not require facilities to keep records of the number of fishes used in experimentation. The rough estimate is that half of animals used in research are fishes.
Zebrafishes are widely used in research because they are bred to be transparent. They are also easier to care for and produce more offspring than rodents. Using zebrafish embryos is also considered a replacement method for animal experiments, even though fishes can feel pain like other animals.
This page will be updated as more information becomes available.
Zebrafish embryos as an alternative to animal experiments—a commentary on the definition of the onset of protected life stages in animal welfare regulations by U. Strähle et al. in Reproductive Toxicology Vol. 33(2) (2012).
Guidelines for the care and use of fish in research by L. DeTolla et al. in ILAR Journal Vol. 37(4) (1995).
Fish as research tools: alternatives to in vivo experiments by M. Schaeck et al. in Alternatives to laboratory animals: ATLA Vol. 41(3) (2013).