Aquarium Basics

Aquarium Water Quality

The presence of plant life and fish overcrowding are two big factors in aquarium water quality.
The presence of plant life and fish overcrowding are two big factors in aquarium water quality.
©2007 Publications International, Ltd.

Aquarium water quality deteriorates for several reasons. As a part of their metabolism, fish produce various waste products that accumulate in the water, and other organic matter such as uneaten food decays into substances that can contaminate the water.

Over time, these pollutants build up in an aquarium to a level that is dangerous to the occupants. In their native environment, fish are protected from this problem by a natural system. The water in a river or lake is continually replenished with fresh rainwater, and different chemical and biological processes remove organic pollutants from the water.

To keep a healthy aquarium, you simply need to understand this natural system and duplicate its effects for your fish.

Prior to the advent of filtration, hobbyists depended on their ability to maintain a balance in the tank. The number and size of fish, the abundance of plants, and the ability of snails and other scavengers to consume excess food and other materials in the tank were all taken into consideration.

It was, however, a balancing act that only the most skilled aquarists could maintain over time. The number of fish that could be kept in these balanced or natural aquariums was rather small. And yet, when measured against the natural environment of the fish, even these aquariums were rather overcrowded.

Today, new hobbyists often believe that aquarium technology, particularly the filtration system, eliminates the work and the problems of keeping fish. Up to a point, this is true.

Certainly in comparison to keeping fish in a bowl, where all of the water must be changed at least once a week, an aquarium with a filter is more convenient and easier to maintain. Still, filtration systems have limitations.

No matter how sophisticated, a filter can only slow down the rate at which the water in an aquarium becomes polluted. No filter system can actually stop water quality from deteriorating. Filtration is important to maintaining good water quality for the fish, and filters do make it possible to keep more fish in an aquarium.

Success with fishkeeping, however, requires more than a good filter. The true value of filtration is that it helps you maintain good water quality more consistently, but only if some easy-to-follow principles of aquarium care are followed.

The real key to success is found in three basic rules, each formulated to create a stable environment for the fish. Rule one is to not overstock the tank with fish. The more fish there are in an aquarium, the faster the water quality goes down. As noted earlier, the filter only slows this process.

The second rule is to not overfeed the fish. The accumulation of uneaten food in the tank will quickly contaminate the water. Rule three is to do frequent partial water changes. This removes pollutants and adds fresh, clean water to the aquarium, helping to maintain a healthy habitat.

If you understand these three rules and the reasoning behind them, you're well on your way to becoming a successful aquarist.

What remains is to learn about the equipment you'll be using -- what you need and why you need it -- and then to learn a little about the fish that you'll be setting up house for. Let's continue with learning where to shop for your aquarium on the next page.

To learn more about freshwater aquariums, see: