How to Take Care of a Fish in a Closed Ecosystem

A closed ecosystem is one that is a microcosm of the kind of ecosystem that you would find in a fish's natural habitat. Within any aquarium, there are a variety of bacteria, algae and other aquatic life that all work together to help support one another. In the aquarium hobby, the self-sustaining aquarium is one of the hardest things to achieve, often requiring years of patience and failure before the system can become self-supporting. In addition, having fish in a closed ecosystem is impossible in all but the largest aquariums with very few, very small fish.

Things You'll Need

  • Aquarium water test kit
  • Fish food
  • Carbon filtration system
  • Aquarium air compressor with a bubble stone
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Instructions

    • 1

      Treat the water that you are using for the aquarium with the necessary chemicals to balance the pH of the water and remove the heavy metals from the water. These chemicals are typically known as tap water conditioners and are available at any pet supply store.

    • 2

      Change 1/4 of the water in the tank every month if the tank is large and supports very few small fish or more often if the tank supports several larger fish. This will help keep pH levels from rising uncontrollably, eventually poisoning the fish.

    • 3

      Test the water regularly using a pH test kit available from your local pet supply stores. These kits test for the presence of heavy metals, chlorine, chloramine and ammonia in the aquarium's water. This will allow you to dose the aquarium properly with the correct chemicals to counteract these contaminants as well as provide you with a course of action you can follow.

    • 4

      Feed the fish a healthy, high-quality fish food that is designed for your specific species of fish. Feeding should be done at most three times per day, and only with as much food as the fish can consume in a five-minute period. Additional food should be removed from the tank if it is not eaten.

    • 5

      Filter the water in the aquarium using a carbon filtration system. Regardless of what type of fish you have, a carbon filtration system must be used to neutralize ammonia in the water.

    • 6

      Aerate the tank to help prevent the water from becoming stagnant. Stagnation occurs when the fish in the tank consumes all of the oxygen in the water, effectively strangling it. In smaller aquariums, the surface of the water is not sufficient to take in enough oxygen to support the fish. Attaching a bubble stone to an air compressor and placing it in the aquarium will sufficiently aerate the water to give the fish plenty of oxygen.