Starting an aquarium can seem daunting. Which kind? How big? Which fish? We'll answer these questions and more.
Fundamentals
Nature has created over 30,000 species of fish. With the sophisticated aquarium systems now available, literally hundreds of them can be successfully kept and bred in the home. The art of fishkeeping can be as simple or as complicated as you care to make it - from a single goldfish in a plastic bowl to a breathtaking display of tropical beauties in a massive glass tank. It's important, though, to consider how much time and effort you wish to put into this new hobby. Your first consideration as a potential fish keeper will be to decide on which type of fish you intend to have in your home.
You can make your choice from four different groups: coldwater freshwater fish, tropical freshwater fish, coldwater marine fish and tropical marine fish. While the first of these types can be successfully kept with very basic equipment, the last will inevitably be the costliest and most demanding of your time and attention. One thing is certain, whatever group of fish you ultimately decide on, you'll need some kind of container in which to house them. Let's take a look at the various types of containers currently on the market and learn how to make them fish friendly and beautiful!
Basic Fish Bowl
Many people keep coldwater freshwater fish (usually goldfish) successfully in plastic or glass bowls. Although in many ways this is the simplest approach to fish-keeping, great care is needed to prevent your fish falling ill, or even dying, from lack of oxygen or from foul water. Remember that a single fish, one inch long (excluding tail), requires a minimum of 1 gallon (3.8 liters) of water to swim in. To keep water oxygenated, a broad-rimmed bowl should be kept full, while a spherical one is better left only half full. To avoid fouling the water, feed only what the fish can comfortably eat in two minutes. Uneaten food, together with the fish's own waste products, will quickly pollute the water, which can in turn become depleted of oxygen. If your fish stops eating and starts gulping mouthfuls of air at the surface, this is an indication that the water should be changed immediately.
You should keep your fish bowl away from windows and direct sunlight (which promotes algae growth), and never stand the bowl where it's likely to be in a draft. Fish are badly affected by sudden changes in temperature, which also means you should follow this step-by-step routine when changing the water:
Stand a bucket of clean water by the bowl overnight to allow the temperatures of the water to equalize. (Don't use a bucket that has contained cleaning agents or other chemicals).
1. A half hour after feeding, net the fish and place it carefully in a small jar filled with water from the bucket.
2. Empty the fish bowl and wipe the inside of it with a clean paper towel.
3. Refill the bowl with water from the bucket.
4. Carefully return the fish to the bowl.
Fish Tanks
Fish tanks are really the best containers for keeping fish indoors. The bigger the tank, the more fish it can hold, and the more slowly its temperature will change. For most hobbyists, an aquarium holding 15-30 gallons (60-120 liters) is small enough to be easily cared for but big enough to make an impression, provide stability in water quality, and hold a reasonable number of fish. A tank with a low profile shape rather than a tall one is preferable, since it will provide a greater surface area for gas exchange. You can figure a tank's capacity by multiplying length by width by height. If using inches, divide the answer by 1,728 to give cubic feet; 1 cubic foot holds 7.8 gallons. But don't forget that a 15-gallon (60-liter) tank will weigh about 145 pounds (65 kilograms) when filled with water, sand and decorations, so be sure that the floor or shelf you're using can support that much weight. Place the tank away from windows, because temperature fluctuations are bad for the fish and too much daylight will encourage algae to grow, cloaking the surface. Every tank needs a loose-fitting, nontoxic lid that will let in air but keep out dust. It will also prevent fish from jumping out, and retard water evaporation.
Plastic Tanks
Molded plastic tanks make attractive small aquariums, and offer some advantages: there are no joints to leak, and the plastic is unaffected by fresh or salt water. Such tanks are rarely large enough to be of service as marine aquariums, however, and the plastic is apt to scratch when algae is removed from the sides. Over time, the plastic also tends to turn yellow.
Angle-Iron Tanks
Angle-iron tanks are made from five sheets of glass fixed into a metal frame with putty. They are strong, but can leak if the putty hardens and shrinks, so they must be maintained by occasionally applying a sealant along the joints between the sheets of glass. If you're planning to use such a tank for marine fish, the metal frame will have to be treated with an anticorrosive, bitumastic paint.
All-Glass Tanks (the best choice of all)
All-glass tanks are made from five sheets of glass glued together with transparent silicone rubber sealant. Strong, economical, and nontoxic, they provide the owner all-round visibility, and remain the most popular choice among fish lovers. They must be placed on polystyrene sheets to prevent the bottom sheet of glass from cracking beneath the weight of the water.