200 million years in the future, virtually all the species of fish have been wiped out, leaving all the niches they filled vacant and Silverswimmers, neotenous forms of crab, have filled that vacancy. Their ancestors were microscopic crab larvae, but now they are as diverse in size and shape as fish once were, and they fill the void in the sea left by the absence of fish. There are hundreds of different species of Silverswimmer and they fill every available niche. Some are predators, some prey, some are parasites and others are scavengers. The program focuses on one filter-feeder type, although a large carnivorous type is shown briefly.

List of speciesEdit

• Common Silverswimers
• Sword Silverswimmer
• Flathead Silverswimmer
• Fish Silverswimmer