Proteolytic dechorionation of annual fish embryos

Incubation of early embryos of Nothobranchius korthausae in sterile Tris-buffered pronase with added salts and EDTA results in complete dechorionation, after which development proceeds normally and at the same rate as in control embryos. The time required for dechorionation varies according to the age of the embryo and the concentration of pronase employed.