Fin clipping as part of the genotyping process

The first step in genotyping adult zebrafish generally is fin clipping. Like the name probably already indicates, it involves clipping the fin of the zebrafish specimen. However, some important protocols must be observed to do so optimally, with as little distress and mortality as possible. First, a water bath is set up to contain 200ml of system water i.e. water used to fill up the fish tanks. To this bath, about 15ml of tricaine should be added. This will anaesthetize the fish, temporarily rendering the fish immobile and unconscious, making the clipping process easier and causing the fish less distress. If the fish does not stop moving when placed in the bath, more tricaine can be added, no more than 10ml. Too much tricaine can kill the fish. When the fish is finally floating sideways in the bath, unconscious, a razor blade should be used to carefully amputate roughly half the caudal fin. Again, living tissue must not be cut, as this will cause the fish to bleed. Bleeding may lead to infection or, worse, death. The clipped fin should be placed in a tube, labelled properly, according to the tank the fish was obtained from and the crosses done to obtain the fish. The fish can, then, be returned to fresh system water. The fish should regain consciousness and become mobile again in about 5 minutes. If this is not the case, then, the fish is probably dead, due to some error in fin clipping. The fin tissue obtained can then be taken to the lab and DNA extracted from it. Subsequent genotyping steps will follow once DNA is extracted.