Complex sentence: The process is known as cisgenesis, where genes are synthetically altered and then transferred between organisms that could be conventionally bred, in this case GM fish, or transgenesis, where genes from diverse species are inserted by means of horizontal gene transfer.
Split into simpler sentences: The process is known as cisgenesis, genes are synthetically altered and then transferred between organisms that could be conventionally bred, in this case GM fish. While transgenesis, is where genes from diverse species are inserted by means of horizontal gene transfer.