You can always put away decorations and fish you don't currently need and have them kept in storage for you 😎
To remove your decorations:
1. Select a decoration to open the object menu at the bottom of the screen 🎃
2. Choose the box icon in the menu 📦
3. The decoration will be removed from your aquarium, and you can then find it marked as Stored in the Store 🎁
To store your fish:
1. Select a fish to open the fish menu at the bottom of the screen 🐠
2. Choose the Scoop Net icon and confirm the action 🕸️
3. Your fish will be removed from the aquarium. You can then find it in the Store under the Fish tab, where it will be marked as Stored 🗃️
If you decide you want a stored decoration or fish back:
1. Open the Store 🏪
2. Select the decoration or fish you want ➰
3. Select Place in the next window to return the decoration or fish to your aquarium 🗳️