What is a Balanced Aquarium?

Originally the concept of a balanced aquarium was that the standing aquarium is a self-contained microcosm - a little world. The theory ran that as the plants manufactured food through the process of photosynthesis; they utilized carbon dioxide and gave off oxygen. Fishes, on the other hand, gave off carbon dioxide and utilized oxygen. Fishes’ waste, according to the theory, fertilized the plants, while excess plant growth provided food for the fishes. One thing thus balanced another, and no outside care was required.

Unfortunately this theory simply does not hold up in practice. While plants do give off oxygen in excess of what they use for respiration, they do so only in the presence of bright light. When the aquarium is dark, they use up oxygen just as do the fishes. Water cannot store more oxygen than the amount required to keep it in equilibrium with the air above it. Excess oxygen passes off readily. The same does not hold true of carbon dioxide. It tends to stratify, forming layers along the bottom. (Circulation prevents this stratification.) Having a maximum air surface in proportion to the depth thus goes a long way toward keeping the aquarium properly “balanced.”

The waste matter produced by the fish is far in excess of the amount required by the plants. Moreover, most of our aquarium fishes are carnivorous, eating animal, not vegetable, matter. Even the more herbivorous species require some animal food.

So the idea of a “balanced aquarium” is a fallacy in its original concept. An “aquarium in balance” is, however, what can be achieved.

The factors that modify an aquarium more or less balance each other includes the proper amount of light (too much over stimulates algae, too little does not permit plant growth); the proper amount of food (too little stunts the fishes, too much pollutes the aquarium); the proper number of fishes; the correct size of aquarium, and the proper temperature, etc. All of these things must be in proper “balance” with respect to themselves and the others if the aquarium is to flourish.

Tropical Aquarium - What is the Best Type of Filter for a Beginner?

From the point of view of satisfactory service over a long period of time, an outside filter is the most satisfactory. Hanging in the rear and outside of the aquarium, outside filters are easily concealed yet readily serviceable.

By their very nature, filters become the repository of all the waste and filth in the tank. They should be cleaned every two weeks, on the average, to remove this waste matter. An outside filter is the easiest to disconnect and remove to be cleaned. Also, it can be examined easily to determine the amount of accumulated dirt. If the tank is located where it does not permit the hanging of a filter on the outside, however, it is necessary to employ an inside

The air lift filter is a closed plastic box containing the filtering material. The air-lift tube is straight, instead of curved, and is set in the middle of the filter in the filtering material. This type of filter has perforated sides and rests on the bottom of the aquarium, usually at the rear. The air-lift draws the water from the center. New water comes in through the perforations and passes through the filter material as it makes its way toward the center.

A bottom filter is frequently used by dealers for several reasons. It requires a lesser amount of air than do outside ones. Many dealers have their tanks banked closely together, and do not have space between them for outside filters. Also, bottom filters double as aerators. The stream of air agitates the water as it rises, serving to aerate and circulate the fluid.

Against this, however, is the reluctance on the part of a fancier to disturb a tank once it is set up. There is a tendency to let a bottom filter remain without cleaning for months on end, until it becomes a focal point for pollution. Far from serving as a cleansing agent, it becomes a menace. The same holds true of the other types of filters, but to a far lesser degree, because there is much less tendency to neglect them.

Because under-gravel filters have disadvantages, I usually recommend that they be used in conjunction with a good outside filter. Thus several areas will be served, and there will be less likelihood of difficulty if the under-gravel filter clogs up.

Tropical Aquarium Aeration and Filtration

Water is the fishes’ atmosphere. It is the medium in which they normally exist and through which they travel, and from which they extract the oxygen so necessary to existence. Just as our air must be pure and contain sufficient oxygen, with no excessive amounts of harmful or irritating gases present, so must the fishes’ water be clean and well oxygenated.

Provision must be made to prevent the accumulation of harmful materials in the water; whether gaseous, solid, or liquid; whether in solution or suspension. The fishes’ water, just as the air we breathe, always contains a certain amount of harmful material; that is, material which would poison the fish if allowed to accumulate above a certain minimal amount.

The atmosphere over every large city contains tons of waste matter such as factory gases and products of combustion. When weather and geographic conditions prevent their dispersal, they can accumulate in such quantity as to inhibit human life. It is this sort of situation which is described as “smog.” The same sort of thing, on a lesser scale, can occur in our aquaria unless we guard against it.

The problem is twofold: to insure a proper supply of oxygen for the fishes to use, and to dispose of the products of respiration, metabolism and decomposition.

Oxygen is the fuel that stokes the furnace of life. This is true of fishes as well as of higher forms of life. The majority of fishes breathe by taking water in through the mouth. The mouth is then closed tightly and the water is forced outward over the gills and through openings at the back of the head. Each of the openings is covered by a flap - the operculum - often incorrectly called the “gills.” The gills are located under the opercula. They are the red branching members seen when the gill flap is lifted.

A few varieties of fishes, such as the Bettas and certain Catfishes, have specialized auxiliary breathing organs which enable them to extract oxygen directly from the atmosphere. However, such fishes are in the minority. It is the gills of the vast majority of fishes that are analogous to our lungs. As the water passes over the blood-rich gill surface, the dissolved oxygen is extracted for the fishes’ use, and waste carbon dioxide is given off.

A fishes’ nostrils are not used for breathing. The nostrils do not connect with the mouth and are used solely as organs of smell. There are a very few exceptions to this, but they are not included among the fishes kept in home aquaria.