How to Use Real Seaweed in an Aquarium

Seaweed is sometimes called macroalgae, and can be used to feed herbivorous or omnivorous animals in a saltwater aquarium. Though some types of algae can easily overrun a tank, cultivating a bit of seaweed--either in a refugium or the aquarium itself--can be both attractive and beneficial to the overall health of your tank's inhabitants. Besides being palatable food for fish, plants help filter your tank's water.

Things You'll Need

  • Deep sand-bed refugium
  • Macroalgae
  • Rock
  • Coral glue or holdfast tissue
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Instructions

    • 1

      Place a deep sand bed in a well-lit refugium. The refugium must receive water from the aquarium's outflow in order to take in nutrients from the aquarium's bioload.

    • 2

      Plant a few pieces of sea lettuce, sargassum weed and/or spaghetti algae in the sand bed. These are fast-growing, nutritious food for herbivores and copepods.

    • 3

      Cut segments of the seaweed and attach to rock with a bit of coral glue.

    • 4

      Place rock with seaweed in the fish tank for the fish to eat. Replace as needed.

    • 5

      Attach spiny seaweed, red grape algae and/or blue ball algae to rock with coral glue or holdfast tissue and place directly in the aquarium. These attractive, slow-growing seaweeds are not likely to take over your corals.