Creative? Maybe, but poor birds. How unnatural and unsuitable for them. Imagine them having to live their days out like that. Sad.

I wonder if the birds like watching the fish.

What happens if the bird falls off the perch (like they sometimes do)? It's a very creative (if not dangerous for the birds) way to keep a cage clean!

That can be a mutualism, the birds give his pup for the fish food, and the fish give an attractive motion for entertain the birds.^^