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What Is Nori and How Is It Used?

Feeding Nori to Saltwater Aquarium Fish and Other Algae Eaters


A difficult to keep species

Black & White Bandit Angelfish (Holacanthus arcuatus)

Image by Keoki and Yuko Stender
Nori is natural seaweed that is roasted or dried, and believe it or not is actually a human food consumption item used in oriental cooking. In particular, the roasted type is most often used as wrappers for making rolled sushi, while the dried type may be used for this purpose as well as making seaweed soup and rice balls. Nori is sold under many different names, just look for roasted or dried seaweed on the package.

When marine aquarists discovered the nutritional value of nori, being high in carbohydrates, protein, vitamins, and especially minerals, they began using it to feed their saltwater herbivores. It is ideal for feeding tangs and surgeonfishes, some angelfish and blenny species, as well as many other types of algae eaters like hermit crabs and snails.

There are usually two kinds of nori to choose from, red, which sometimes looks dark purple in color, and green, but occasionally fish stores may carry a brown type that is often favored by some surgeonfish species. It usually comes packaged in full sized sheets, but you may find it already cut up into pieces and prepackaged by some aquarium stores or suppliers. We have always bought nori from the oriental food section of our local grocery store, packaged in 10 - 8 inch x 8 1/2 inch sheets. Our preference is towards the green kind, because it seems to dissolve more slowly than the red, making feeding with it a little less messy. Be careful when buying nori in grocery stores. Flavored types are sold, such as teriyaki, and you want to avoid these.]

Having used nori to feed our captive marine life since 1989 with no problems, it is interesting that we have heard mention that this product may introduce phosphates into aquariums. For this reason some aquarists do not recommend it as a food source, but if you are concerned about this potential problem, there is a simple solution. Before you start using it, just run a test on the aquarium water to check and see if the phosphate level is acceptable, then perform tests regularly over a period of time after you begin feeding with nori to see if it may be contributing to a PO4 build up in your system.

Next Page > How To Use and Store Nori

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