An aquarium provides a useful and interesting teaching aid for the classroom. Students observe growth and development of plant and animal life, community relationships, feeding habits, and predator-prey relationships. The design should be a biosphere in which plants and animals survive and grow with little care.
Each classroom is different; therefore, the following requirements need to be considered before finding a permanent location for the aquarium. Avoid wide-range fluctuations in light and temperature. Natural light may be controlled by blinds or shades at the windows. To reduce the rate of evaporation and sudden temperature changes, do not place the aquarium in a direct airflow from a heater or air conditioning duct. Artificial light may be used. In the interest of safety, consider the traffic pattern in the classroom.
The aquarium needs to be thoroughly rinsed with water. NEVER USE SOAP in an aquarium. Soap is difficult to rinse out, and any residue can kill the organisms. To remove water marks or mineral deposits on the glass, apply towels soaked in vinegar. Rinse with water afterwards. Fill the aquarium with water and check for leaks. A small leak may seal itself by the weight of the water pressing on the glass. If a leak persists, the aquarium must be emptied, dried, and sealed with silicon. After the water is added to the aquarium, it must be cycled for at least a week. The ideal water temperature is between 65 to 75°F. The aquarium may be covered by a piece of glass, Plexiglass, or plastic wrap to reduce evaporation or airborne contamination. Care must be taken not to seal tightly and restrict the air exchange.
The aquarium may be layered with a 2-inch layer of small gravel. Any gravel or rocks must be thoroughly washed prior to adding them to the aquarium.
Plants provide a cover for small fish, remove nitrogenous waste released by animals, and absorb carbon dioxide. The primary considerations in the choice of plants are based on the light conditions and the size of the aquarium. Elodea, duckweed, and Vallisneria require high light conditions. Chara (a stonewort) and Vesicularia (an aquatic moss) do well in low light. Duckweed and Vallisneria are best suited to aquariums 10 gallons or larger. Elodea, Chara, and Vesicularia may be floated on the surface or rooted in the gravel. Vallisneria needs to be rooted in the gravel. Duckweed is a floating plant that multiples rapidly. Harvest (remove) some of the duckweed whenever it covers the surface of the water so that it will not restrict light and gas exchange.
Fishes & Other Aquatic Creatures
After a week or so, your aquatic friends may be added to the aquarium. Allow 3 inches of fish (vertebrates) body-length per each one gallon of water. Float the bag of fish in the water of the aquarium for 20 minutes before adding the fish to the aquarium to reduce stress on the fish. Snails (invertebrates) add interest to the aquarium. In the spring frog eggs, tadpoles, or salamanders may be found in nature. Unless you are able to classify these organisms to determine their dietary requirements, practice sound environmental procedures and leave them undisturbed. Hydra and daphnia may be added to demonstrate specific food chains or predator-prey relationships.
Check the aquarium daily for dead animals or plants. Remove accumulated waste from the bottom once a week. Replace one-third of the water each month with aged water. Feed animals at regular intervals, never feeding more food than can be consumed in 30 minutes. Remove the remaining food to reduce a build-up of organic wastes, which clouds the water and lowers oxygen concentration. Flake food available at pet centers is a good basic diet. Brine shrimp eggs may be hatched, rinsed in fresh water, and fed to fish and invertebrates.