The rare decoration in a set is marked by a blue question mark. That is the one you should try to obtain. The more decorations you unlock, the better your chances to get it. Be careful not to tap the double arrows icon, or the board will be shuffled and force you to start again. Always save a few decorations in your inventory to use when you unlock a new area.
Fish
When starting, do not be overly concerned about the types of fish that you can get. Simply be sure to have the maximum amount floating around and feed them until they become adults. This allows you to get more ingredients for the more difficult to obtain fish. Releasing a certain number of fish in each set earns you a set mastery, which gives you rewards such as premium tickets for the Hermit Crab. Use the basic breed, the first fish that is available. A lot of them are required to get the materials for the more difficult to obtain fish. Consider focusing on a set at a time.
Keys
Keys are rewarded when you level up. Always feed the fish and release them in order to gain experience and level up. Keys are used unlock new areas and new sets of fish.
Splashcash
Splashcash is the game's premium currency. Occasionally it is dropped by fish.
Upgrades
Upgrade your inventory to hold more items. This is very useful later, when a large number of materials will be required. The Green Food Pot gives you food discounts for each upgrade level. Note: Getting materials to do this is very difficult due to the rare amount of drops.
