I gathered a couple of supplies that I had on hand, some squirt-y fish, turtles, and gems.
I bought a large package of pasta at the dollar store, and I cooked it and added blue food coloring to it. I put oil in the pasta to keep it from sticking, so I put the kiddo in some play clothes. Next time, I might forgo the oil and just add a bit of water. Logan took it upon himself to take on the important role of taste tester prior to playing.
Once it had his seal of approval, he set up the rest of the bin himself. It was his idea to add the water to the bin. His most favorite part was swishing his hand around while the pasta brushed past it. He also enjoyed finding the fish throughout the "kelp forest." (Thank you, Octonauts)!