Many an interested amateur might have installed an aquarium of goldfish in the living room long ago if he had not been frightened by the idea that it entails a lot of expense, particularly the cost of an air pump which he has been told is necessary. Not so. Air pumps are used advantageously by pet-store operators who must crowd a lot of fish into limited quarters. Such pumps, however, certainly are not necessary for aquariums that are not overcrowded. Follow the capacity rule in stocking an aquarium, add a few oxygenating plants, place the aquarium where it can get the required sunlight, and you will have no need for a pump. Neither will you need a trickle of running water, another petstore device. In fact, either an air pump or running water can keep in constant turmoil an aquarium which otherwise would soon become well balanced.

   Make your own choice. Personally, I have an aversion to most goldfish bowls because it annoys me to see the fish kept in small containers which are little more than prisons. If you buy a bowl, buy a big one, 10 or 12 inches in diameter, and do not overcrowd it. The keystone and the flat-sided types illustrated here are the most efficient designs you will find. If you choose a small container, do stock it accordingly, perhaps with only one fish.

   Flat-sided, plate-glass aquariums are the easiest to keep clean, give you the best show, and are inexpensive, particularly if you can find one second-hand. Being fragile, they do not travel as safely as other household effects when a family moves. For this reason, aquariums show up frequently as used, but still usable, merchandise in second-hand stores, junk shops, and at auctions of household goods.

   However, new aquariums of standard shapes and sizes are not expensive. Even aquariums which are custom built for some special scheme of decoration are reasonable enough.

   An aquarium out of use for a long time will often leak when first filled again. If seepage at the seams is slight, throw a handful of mud into the water and stir it up. Then let it set overnight. If this fails, empty the aquarium and apply stiff, clean clay as caulking around the inside seams. Finally, if the aquarium continues to leak, empty it, wash it thoroughly, dry it, and then cover all cracks along the inside seams with a good grade of waterproof varnish or fill with plastic cement. Don't try to repair a leaky aquarium while it is full by applying waterproofing solutions to the outside seams. This has never been known to work.