Keeping fish in an aquarium is said to be one of the top hobbies in the United States today. Some enthusiasts search for antique-looking aquariums that fit with room styles from the past. It was not a hobby for an average householder until the 1830s, when the Wardian case was created as a simple container for live fish. By the opening of the Crystal Palace Exhibition of 1851 in London, aquariums were wonders suitable for a home, and two years later the London Zoo built a large aquarium open to the public. The United States had enough people interested in raising fish indoors to form an "aquarist society" by 1843, and fish became part of a full-blown fad by the 1860s. Of course, that meant there were things to collect - an aquarium and equipment - like pumps and filters, rocks, small figures and scenery for the fish tank. Decorators planned rooms with planters and aquariums in the prevailing styles of the time, from Victorian to Mission to Art Deco to modern. Old tanks made of wrought iron and glass, tanks bordered by heavy Mission-style oak planks, glass bowls held in wicker stands, and Art Deco designs using plastic instead of glass are sometimes found at antiques sales. And the small glass fishbowl for guppies or goldfish so popular in the 1950s still is available. Recently, a Deco aquarium made of wrought iron vines and leaves, and a clear, slightly green glass bowl was sold for $805. It had a light at the top and a holder for a large potted plant at the bottom. It's probably the focal point of a room today.