All the fish and decorations that have been put into storage can be found at the very top of the corresponding tabs in the Store where they're labeled as Stored 📦

For example, if you put a unique fish in storage, it will appear at the top of the voucher-icon tab 🎟️

Please note

1. All of the event decorations that you put in storage will go to the tab marked with a tower icon along with regular decorations 🗼

2. Thematic decorations that are connected to particular aquariums will go to the corresponding tab for storage. For example, if you want to pull up a stored Amphitheater decoration from the Greece aquarium, you'll need to go to the tab with an aquarium icon and then select the column icon at the bottom of the Store window to open the corresponding tab.