Throw some live mussels or oysters or clams or even scallops, also limpets would go well and Hermit Crabs! You might as well turn this pond into an Indoor tide pool! Add a little kelp, a small starfish or two, a baby octopus, small surf perch or sergeant majors, an abalone! Sea slugs, squirts ,cucumbers kelp crabs etc.
I should be doing school right now but I’d rather be watching your videos 🔥. You should definitely add a baby shark or stingray! Keep up the great work!