Algae in Tropical Tanks

The appearance of algae in a fish tank should come as no great surprise. Algae are similar to plants, and given water and the right mix of nutrients and lighting, algae will grow. The best that an aquarium owner can do is try to limit the growth of algae by making the conditions less than ideal and by using algae eaters to help control growth.

  1. Nutrient Control

    • Managing the levels of nitrogen and phosphate in the water can inhibit algae growth. Testing kits for nitrogen and phosphate are available at most aquarium shops. Nitrogen is best maintained in the range of trace to 25 parts per million, and phosphate levels are ideally kept to trace amounts. Regularly changing part of the aquarium water is also a good idea as algae grows better in standing water, such as ponds, than it does in moving water, such as a river or stream.

    Plants

    • Plants are another good way of controlling algae, because both have largely the same growing requirements. Forcing algae to compete for resources can help keep algae growth under control. In addition to soaking up nutrients that the algae need to grow, tall plants can block the aquarium light which is essential to algae growth. Before adding new plants to an aquarium, wash them thoroughly to avoid the risk of introducing new types of algae along with the plants.

    Lighting

    • Many aquarium owners find a soft light in the tank appealing. It is important to remember that in nature, though, most underwater environments are not brightly lit. It is important to expose the aquarium to as little natural sunlight as possible and to try to keep the aquarium lights on for no more than 10 to 12 hours per day. Algae grow when they get enough light and nutrients. The more light the aquarium gets and the more crowded it is with fish, the better algae will grow.

    Algae Eaters

    • Many tropical fish eat algae. This is especially true of bottom-feeding fish. It's important to remember, though, that algae eaters need something to eat. In a newly set up aquarium or an aquarium that has been kept completely free of algae, algae-eating fish may go hungry. If there is enough algae in the tank to need to control it, various types of algae eaters make interesting additions to a tropical aquarium, including catfish, loaches, Siamese or Chinese algae eaters, clown fish and plecos. Types of shrimp and snails can also help control algae in tropical tanks.