Sorry, no fishes, many other foods contain purines, notably anchovies, goose, mussels, scallops, yeast, and meat derivatives such as soup stock and gravy. But avoiding purine-containing foods may not be as necessary as it was once thought to be.

Gout is a heritable disease marked by an excess of uric acid in the blood. Severe dietary restriction for people with gout can indeed decrease blood levels of uric acid somewhat. However, today's medications, especially allopurinol (Lopurin, Zyloprim), can do the job much better. So moderation in diet ration than avoidance of certain foods is sufficient for most people with gout.
Alcohol, however, is one dietary item that should be restricted, since it may trigger an acute attack of gout. And good luck.