The second, more likely possibility is that the egg fused with two sperm cells and created a triploid cell.
In Arizona a mutant Chinese grass carp, the sterile triploid amur, has been released into the ponds and water hazards of golf courses to keep the water free of entangling weeds .
For instance, the triploid oyster, still in the experimental phase, is rendered sterile with antibiotics and thus does not go through an uneatable mating phase; it is harvestable .
GONE FISHING WITH JERRY MILLER : Report on Lake Jacksonville By the end of this month the Parks & Wildlife Department will make a major announcement concerning the protection of Triploid grass carp that were introduced into Lake Jacksonville about seven years ago.
June 17, 2013 - Jacksonville Daily Progress