How to Increase Algae Growth With Plecos

The plecostomus, or "plecos" fish, are voracious algae eaters. Some species can become quite large, while others will remain a few inches long. They are great additions to the community aquarium. Plecos are tropical freshwater fish and need water temperatures of about 75 degrees. Some species can be kept in planted aquariums, but they need to be well fed to prevent them from eating the plants. Encouraging algae growth in the aquarium is one way to provide a natural food source for plecos.

Things You'll Need

  • Aquarium plant fertilizer
  • Compact fluorescent lights
  • Carbon dioxide canister
  • Carbon dioxide diffuser
Show More

Instructions

    • 1

      Increase nitrates in the aquarium. Nitrates are produced through a process called the "nitrogen cycle," in which ammonia excreted by the fish and other animals is turned to nitrite by bacteria. Another type of bacteria turn the nitrite into nitrate. Nitrate is toxic to fish in high quantities, but is a fertilizer for algae and plants in the aquarium. You can produce high nitrates by adding a bit more food to the aquarium and performing fewer water changes. Be very careful, though, because nitrates will kill the fish if they are in too high of a concentration.

    • 2

      Increase the level of phosphates in the aquarium. Phosphates are another fertilizer for algae (and plants), and increasing their level in the aquarium will encourage algae growth. You can increase phosphates by feeding the fish frozen foods, such as blood worms and brine shrimp. You can also add aquarium plant fertilizers to the water.

    • 3

      Inject carbon dioxide into the water. This is a common practice to encourage the growth of live freshwater plants, but it will encourage algae growth as well. You can purchase compressed carbon dioxide from some aquarium stores and connect the bottle to the aquarium with a plastic air hose. A few bubbles per second is all you need. A diffuser will help the carbon dioxide dissolve into the water better.

    • 4

      Increase the amount of light the aquarium receives. Consider using compact fluorescent 10,000 Kelvin bulbs. Its name refers to the temperature of the bulb and the type of light it emits. These bulbs are similar to daylight. Another way is to allow direct sunlight to enter the aquarium. But monitor the water temperature if you use direct sunlight because it can make the water too hot.