Painting water and fish

My three-and-half-year-old son seems to have nursing a dream of becoming an artist. He would come to me with his small box of water colours and brush and ask me to fetch him a bowl of water and a notebook. This morning, he repeated this request and I obliged (I have to). After sometime, I saw water all over the page with a few strokes of blue. I scolded him for spoiling the notebook. "Father, this is a painting of a water tank. Don't you know, water tank contains water," he replied. This is not all. He, then, asked me to paint fish. I opened another page and drew a couple of fish. He protested saying, "Father, you should paint the fish in the tank. They can't survive out of water."