Freshwater Aquarium Care and Mainteance

Dip your hand into a tropical aquarium and you’ll find the water pleasantly warm. This is not surprising since the fishes in the aquarium come from that ‘middle band’ around our world broadly within the Tropics of Cancer and Capricorn where continual warmth is taken for granted. Spin a globe slowly in your fingers and you’ll see that within that band lie the lush jungles and dry grasslands of Africa, the colorful subcontinent of India, the steamy archipelagos of Southeast Asia, the northern reaches of Australia, the sprinkled atolls of Melanesia, Micronesia and Polynesia, and across the vast Pacific to the prolific regions of Central America and northern South America. Add to these land masses the fertile seas that lap their shores, often embroidered with a rich tracery of coral reefs, and you can easily realize that the few fishes contained within a tropical aquarium represent merely a captive drop from a natural reservoir teeming with color and variety.

Choosing Tropical Fishes

From the vast variety available, which tropical fishes fare best in an aquarium? The easiest to keep are those that live in fresh water — in tropical lakes, rivers and streams. The tiny Neon Tetra from the fertile waters of the Amazon is a popular example of the many active shoaling fishes that bring movement and a sparkle of iridescent color to our private ‘windows’ on the tropical world. By contrast, many freshwater fishes, such as the curious Catfishes, are sluggish and secretive, becoming active only during the hours of darkness as they search for food at the bottom of the tank. Between these two extremes are countless freshwater species of various shapes and sizes that will live happily in an aquarium.

Choosing fishes to live together in a freshwater aquarium demands a certain care; the tranquil waters of a stream or lagoon can hide a bitter conflict. The life-and-death struggle of predator and prey or the capricious jealousy of rival males is intensified in the closed confines of an aquarium and in a short space of time only the finest will survive.

Making Them Feel at Home

The tropical aquarium is literally a life-support system. It must simulate the surface layers of a jungle pool, the leafy margins of a slumbering stream, the sun-drenched shallows of a coral reef. The fishes depend upon its proper functioning in the same way as explorers on the moon depend upon their back-packs. And size for size they may be just as far from home.

Water, Light And air

Water is a fish’s atmosphere. The fish absorbs oxygen from it and expels carbon dioxide into it through the gills. To keep the water high on oxygen and low on carbon dioxide it needs to be open to the air. That is why aquariums are longer than they are deep so that no part of the water is too far away from the surface. The stream of bubbles that you see rising in most aquariums keeps the water surface turning over to help this exchange of gases to occur.

Most freshwater tropical fishes will live happily in tap water. If you buy them from your local store then they will be quite used to the quality of your local water. Some fishes will thrive only in soft, slightly acid water, while others need especially hard, alkaline water to flourish. These species are generally those that need extra care for success and are not usually recommended for beginners.

Lighting the aquarium performs two functions: it shows off the fishes to their best advantage and it simulates the natural light levels the fishes and plants need for normal growth and development. Fluorescent tubes are the most widely used form of lighting and most tanks should be illuminated for about 12 hours a day. Marine tanks are usually more brightly lit to reproduce the conditions of a coral reef.

Some fishes, particularly those that become active during the night, should be kept in fairly low light. If the aquarium contains a mixed population of fishes then floating plants can be used to create dim areas to suit these species.

Warmth, Food and Shelter

Tropical fishes need to be kept warm; a temperature of 75-81°F (24-27°C) will suit most freshwater species. This can be achieved easily and reliably with modern thermostatically controlled aquarium heaters.

Feeding tropical fishes has also been made easier by modern products. Dried, flaked, granulated, freeze-dried and liquid convenience foods are readily available to suit most fishes at all stages of their development. Live foods, such as worms and small crustaceans, are also an important part of the diet. Resist the temptation to overfeed.

‘Aquascaping’ freshwater tropical tanks with gravel, rocks, logs and aquatic plants is not a purely decorative pursuit. Some tropical fishes need the shelter of rocks to establish their own territories and hiding places and all benefit from the oxygen-enriching photosynthesis of living plants. A varied underwater landscape may also play a vital role in the breeding behavior of many species.

Health and Cleanliness

Since the tropical aquarium is a living system the natural processes of decay and putrefaction are constantly at work. Waste products from the fishes would quickly poison the water if this was not filtered and partially refreshed with new water every few weeks.

In ideal conditions disease is kept at bay, but poor nutrition, low temperatures and bad handling can make tropical fishes more susceptible to infection. Pests and diseases may also be introduced into the aquarium on plants and on new, unquarantined fishes. Fortunately, modern remedies are effective against the most common ailments and are easy to administer. Regular maintenance of equipment and sensible precautions against disease should keep the denizens of our underwater world in radiant health.