I hope you are kidding! For one no you can't just flush a fish! They die a painful death and um... goldfish can live for 20 years and unless he is 19 years old, he is not old. Ok also not even a goldfish can live in a bowl and a clownfish? I am pretty sure a clownfish needs AT LEAST 30 gallons and infact a goldfish needs 20. Also a clownfish is saltwater and since you seem to not know anything about fish it is not reccomended. By the way a clownfish is usually $30 or more!