Plants and Coral — Live or Artificial?
Plants and coral are often considered to be mere decorative items by the aquarist, but both are actually living components of the habitat that you establish. Whether to use living or artificial plants and corals will depend upon a variety of factors, including the nature of the animals you have and your degree of experience in aquarium keeping.
Living plants are, of course, interesting in their own right, and their use can result in the establishment of stunning displays. They will also help keep the aquarium clean by utilizing the waste products of the animal inhabitants and will benefit the overall environment by producing oxygen and removing carbon dioxide. Plants can be arranged to fit specific needs within the aquarium, providing, for example, dense shelters for newly hatched fry or sight barriers for shy creatures. Plant roots prevent the gravel from becoming impacted and discourage the formation of potentially dangerous pockets of anaerobic bacteria.
Plants, of course, require nutrients and light of a specific wavelength. If you are keeping fish or invertebrates that are not particularly light sensitive, living plants will add additional complications to your aquarium setup. Plastic plants and marine algae are available in a variety of lifelike models. The utilization of artificial plants allows you to create specific effects with a degree of detail that may not be possible with live plants. Artificial plants will take on a more naturalistic appearance when interspersed with live plants, or if you allow green algae to grow on them.
Be sure to use only artificial plants that are specifically manufactured for use in aquariums. Plants designed for decorative use may have internal wire supports that will eventually rust and poison the water in your aquarium.
Coral, like plants, can be utilized in a living or nonliving form in the aquarium. However, the decision to use live coral must not be made lightly. Coral animals are living creatures that survive by filtering microscopic food particles from the water, and their maintenance in home aquariums is a science in and of itself. Most coral animals are extremely delicate and require excellent water quality and very specific types of food and light. In general, you should only consider keeping live coral if you are an experienced marine aquarist.
Coral skeletons, on the other hand, may be used to great advantage in saltwater aquariums. However, many countries, including the United States and Australia, prohibit the collecting of any form of coral. People in Indonesia, the Solomon Islands, and other locations are now beginning to farm coral. The collection of coral and coral skeletons has caused environmental havoc in many parts of the world and should be strictly avoided. The fact that coral skeletons are offered for sale in a store or online does not guarantee that their ownership is legal. Be sure to research local laws concerning this. Also, be aware that coral legally purchased in another country will not necessarily be legal to possess in your own country.
The same considerations that have been mentioned regarding the use of plants may be applied to coral skeletons as well. They should be arranged to provide the creatures under your care with as natural an environment as possible. The unique shapes of coral skeletons render them particularly useful for creating caves, hideaways, and sight barriers. Coral also assists in maintaining the high pH required by many marine animals.
Coral skeletons must be carefully cleaned, as even pieces long removed from the ocean may harbor harmful organic materials deep within their structures. It is best to clean coral by allowing it to soak in a solution of 8 percent household bleach. The water in which the coral sits should be aerated throughout this period. After this process, the coral should be thoroughly rinsed and allowed to dry, preferably in the sun.
Extremely realistic coral replications, fashioned of various resins, are now readily available in the pet trade. When artificial coral is used in an aquarium that is planted with living macroalgae, they are virtually indistinguishable from the real thing, especially after they have acquired a covering of algae or sessile invertebrates. The wide variety of species and sizes available allows the aquarist to create virtually any habitat he or she may desire.

