Feed Us (the piranha puzzle series) relies entirely on observation, experimentation, and logical deduction. Cheat codes would instantly ruin the core experience. The developers released none.
Search "Feed Us 1 walkthrough" or "Feed Us level [X] solution" on YouTube or GameFAQs. Video guides show the exact sequence without spoiling the entire game.
The satisfaction of the "click" moment is the reward—don't rob yourself of it.