Fish vs. Crabs is a fully immersive 3D underwater Tower Defense Game. You play the role of the fish defending your eggs from invading crabs, shrimp and lobster. The invaders advance along the sandy ocean bottom toward their goal. You must strategically place your towers in an effort to prevent the invaders from reaching your eggs and escaping with them.
Once you have successfully defended your eggs, they are taken to a protected reef that you see as your main game menu. This reef is unique to the player and you may customize this reef by adding and removing corals, sponges, rocks, other fish and special items that you may discover during game play.
In addition to the standard tower defense game, Fish vs. Crabs has other small games built into it. By discovering hidden objects around the reef and completing objectives with those objects such as raising the flag on the pirate ship, the player will unlock additional corals, sponges and other items that may be used to decorate the reef on the main menu.
Source: The Developer Website.