I am looking to put some goldfish in with my 15 year old goldfish. He is about 14 inches long, gold and white spotted, and lives outside all year round in a tank. (summer in a 300+ tank and in winter a heated 200+ tank.) Both have a good supply of algae which he thrives on. I won him at the fair so I don't even know what kind of goldfish he really is. Koi are a little too pricey for me since they are $15 and up. I want something that won't be able to fit in his mouth or will grow fast enough where it won't fit in his mouth. Any ideas? I was thinking of just common goldfish.