no. a person cannot be carrier of a dominant genetic disorder. if a certain disorder is a result of dominant gene both the homozygous and heterozygous individuals are sick and no one of them is carrier. The carrier state is seen only in a situation where genetic disorder is expressed when individuals inherits recessive alleles each from each parent. for someone to be a carrier in this situation, he/she must be heterozygous for certain disorder that is only expressed when an individuals is homozygous of recessive allelles.
When you do that the fish will die. That is because it will take too much water in it and die from it, or rather, the fish's cells will take too much water in.
