Microalgae comes in many varieties and several colors. The two most common colors are Brown and Green. There are some general characteristics of both of these algae that reef ornamental enthusiasts should be aware of.
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Brown Microalgae |
Green Microalgae |
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Digestibility
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Very Good!
Thin membranes are quickly and easily digested, releasing the nutrients. 90-98% bioavailability.
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Poor
Tough cell walls are difficult to digest. 15-25% bioavailability.
Exception: Rotifers have special enzymes that allow them to digest green algae.
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| Omega-3's |
Good
Browns produce all three of the critical Omega-3's - EPA, ARA, and the most valuable - DHA.
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OK.
Green algae typically only produce EPA and ARA. |
| Algae Species |
The best and most commonly used in commercial aquaculture facilities are Isochrysis, Pavlova, Thalassiosira, and Chaetocerous.
One species that is sometimes seen in the ornamental market but very seldom in commercial aquaculture is the diatom Phaeodactylum tricornutum.
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The best and most commonly used in aquaculture are Nannochloropsis and Tetraselmis.
Chlorella is also used, but ONLY for growing rotifers. It is a freshwater algae and has no enrichment value.
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| Smell |
Browns algae have a strong odor, but not unpleasant. It typically smells much like dried kelp on a beach. |
Green algae tend to have a pleasant, soft odor, a combination between grass and hay. |
