Thank you so much!
For this puzzle, you're meant to explore and find hints that reveal the correct order. I'll look into making this more obvious in the future ^^
Note that if a "!" button appears when entering a room, you can get a hint as to what to do in said room :B
You can find a walkthrough here: https://www.patreon.com/posts/119207938
And finally, the correct order is:
1. Leftmost symbol (small fish)
2. Sixth symbol from the left (trilobyte/worm)
3. Seventh symbol from the left (narwhal)
4. Second symbol from the left (turtle)
5. Fourth symbol from the left (bubbles)
Thank you again, it means a lot ^^