Age is not much of a factor with these breeds, for in an aquarium the lifespan ranges from 10 to 20 years. In outdoor pools, they often live beyond the age of 30 years.

   The size of the hardy goldfish you select will also be a matter of personal choice. Remember that goldfish have the characteristic of adapt- ing growth to surroundings. They grow slowly, if at all, in a small aquarium. The larger the aquarium or pool, the larger they will grow. The fancy breeds require a little shopping. Age is a factor with these fish, for their lifespan in an aquarium (few are considered hardy enough for outdoor pools) ranges from only 6 to 12 years.

   Early or mid-autumn is a good time to buy these fancy breeds. A fancy fish 11/2 to 2 inches long (excluding tail) at that time will probably have been hatched only the preceding spring. At this age, they are ideal stock with which to start, big enough to stand the shock of being moved into a new aquarium, still so young that they do not yet show their distinctive tail and fin developments. If you are interested in fancy fish at all, you will undoubtedly want to see their growth from the very beginning.

   Buy a fully developed fancy fish, by all means, if one catches your eye. But remember that once a fancy fish has achieved its most beautiful fin and tail forms, the remaining years will be declining years. Disinfect new goldfish, too, as you did the aquatics, before putting them into their new home. A two-hour swim in a solution of potassium permanganate, V^-grain tablet (from the drugstore) to 1 gallon of water, will kill almost any bacteria they may have brought along and also help them recover from the shock of moving.

   Scrub your aquarium with practically any preparation that cuts dirt well for you in other household jobs, and rinse it thoroughly before putting it back into service. Accumulated dirt and algae on the sides are best removed by scraping with a razor blade, then scrubbing with soap or detergent and water, with or without ammonia added. Use a plastic or copper sponge on the stubborn spots. Do not scour with sand or other abrasive, as this in time will dull the glass with hundreds of minute scratches.

   Whatever kind of an aquarium you have and wherever you place it, the water will eventually take on a greenish color, the result of the growth of millions of tiny aquatic plants, mostly algae. How did the algae get there? They could have come in the front door, through the screen of an upstairs window, or ridden in on your shoulder.