The performer displays a glass filled with ink and sets it on his table. He proceeds to show that it is real ink by inserting a white piece of cardboard into the glass. The cardboard is removed and the end is now black. The magician now covers the glass with a silk handkerchief. He says his magic words, and removes the silk to reveal, to everyone’s astonishment, a glass not filled with ink anymore, but crystal clear water… and live goldfish!

You supply the goldfish for the trick.