Actually he would need to bring every fresh-water aquatic animal. The water that covered the Earth would be saline, since salt water makes up well over 90% of all the water on the planet. Fresh water fish would die.
and if he had taken young representatives there would have been plenty of room.
There's plenty of room for two of every wild and seven of every domestic animal on a boat 450 feet by 75 feet? Are you kidding me?