SPIRULINA ALGAE —
Superfood for Ornamental Fish
Spray-dried Spirulina powder (Arthrospira platensis), is one of the most concentrated sources of protein available for use in the feeding and cultivation of aquatic animals. More accurately identified as a blue-green cyanobacterium, spirulina powder contains valuable nutritional, medicinal, and color-enhancing compounds of interest to fish-keepers.
Early interest in Spirulina focused mainly in its potential as a source of protein and vitamins. Spirulina is as much as 60-70% protein by dry weight. Grown in alkaline waters, it is also an excellent source of trace minerals. Spirulina contains significant amounts of calcium, niacin, potassium, magnesium, B vitamins and iron.
Spirulina powder is of particular interest to ornamental fish-keepers with an economic interest in the visual appeal of their fish. Spirulina is a rich source of carotenoids, containing ten times the beta-carotene of carrots (Algae Industry Magazine, March 2011). Spray-dried spirulina contains 3000-4500 ppm of carotenoids* consisting of zeaxanthin, β-carotene, echinenone and others.
Shrimp and koi, two oft-studied aquatic animals with respect to pigmentation and color, when fed spirulina convert these carotenoids to astaxanthin as evidenced by increased pigment deposition in the carapace and scales, respectively. Inclusion rates of as little as 3% spirulina in the diet resulted in better growth, coloration and feed conversion in shrimp than those fed no spirulina (A Review of Spirulina as a Carotenoid and Vitamin Source for Cultured Shrimp, Lorenz, Spirulina Pacifica Technical Bulletin #050, Nov. 1998).
Of equal importance to aquarists, research shows that spirulina powder included in the diet can have a positive therapeutic effect in cultured fish. Spirulina contains phycocyanin and phycocyanobilin –two compounds associated with antibacterial, antifungal and antiviral activities (Spirulina: An Important Source of Nutritional and Medicinal Compounds, Journal of Marine Biology, Vol. 2013).
Diets containing relatively small amounts of spirulina can reduce reliance on antibiotics and other toxic medications. Antibiotic resistance in aquaculture has also generated interest in spirulina as a natural immuno-stimulant in both fish and shrimp, effectively boosting the immune system in these animals to function at a higher level of activity (Live Spirulina as a growth and immunity promoter for Nile tilapia challenged with pathogenic Aeromonas, Ahmad, 2009).
Orally feeding your fish a diet containing Spirulina could effectively reduce or eliminate the need for bath treatments. Using Spirulina algae as a "prophylactic" treatment in place of antibiotics can effectively reduce wastewater pollutants, eliminating costly treatment systems and increase the effectiveness of existing systems.
*Levels of carotenoids in spirulina vary depending upon growing conditions and other factors.