There are two ways to handle this:
1. Squeeze a few drops of lemon juice into the egg mixture. Lemon itself has the effect of removing the odor, add a few drops of lemon juice, you can get rid of the fishy smell of the egg itself, but also can help the egg whites whipped foam more durable.
2, add a few drops of vanilla extract or vanilla seeds. Vanilla has a strong flavor and can mask the fishy taste of the eggs themselves.