Friends and Neighbors
Visit the tanks of your friends and fellow "Happy Aquarium" players. You will have more success with this task with a long list of friends. Now is the time to enlist more friends if you haven't already. Friends, or neighbors, are helpful to have in "Happy Aquarium." Through them, you can acquire coins and items from treasure chests, receive gifts and earn XP by cleaning tanks.
Sea Shells
The task at hand is to help the princess find her missing shells. There are nine shells to collect -- three common, three uncommon and three rare -- and you may have to go through your entire neighbor list before finding even one of them. The nine shells you are looking for are -- in order from most common to least -- the Golden Shell, Pink Shell, Blue Shell, Green Gold Shell, Brown Yellow Shell, Fuchsia Green, Purple Shell, Dark Pink Shell and Star Shell.
Treasure Hunt
Visit your neighbors' tanks and click on their treasure chests. Each time you do so, you will get coins and maybe a shell. Be persistent. The rarer the shell, the more time it will take to locate it. Be prepared for this challenge to take some time. Once you have located all nine shells, the special item -- the Seashell Temple -- will be available in your tank.
Decorate
All nine shells and the Seashell Temple will be yours to use in your tank once you've completed the task. A well maintained -- clean, spacious and decorated -- tank will earn more XP, allowing you to advance to higher levels and eventually purchase larger tanks for more baby fish.