How to Culture Tetraselmis: A Green Powerhouse for Your Reef

Tetraselmis is a vibrant green flagellated microalga loaded with essential fatty acids, amino acids, and phytonutrients. It’s highly nutritious for copepods, rotifers, bivalves, and other filter feeders, making it a top-tier choice for marine aquarists and aquaculture setups.

What You’ll Need

• Tetraselmis starter culture

• F/2 fertilizer or similar nutrient blend

• Saltwater (1.018–1.022 SG)

• Strong full-spectrum light (6,500–10,000K)

• Air pump + rigid airline tubing

• Sterile culturing container (plastic or glass)

Culturing Steps

1. Prepare the Culture Medium
Mix RO/DI water with marine salt to a salinity of ~1.020. Add F/2 nutrients. Let it stabilize at room temperature (20–28°C).

2. Inoculate
Add your Tetraselmis starter culture. Swirl gently to distribute cells evenly.

3. Aerate
Use gentle, steady aeration with a rigid airline. This keeps the cells suspended and oxygenated while preventing clumping.

4. Light It Up
Provide 12–16 hours of bright light daily. Tetraselmis thrives under strong illumination and displays a rich green color when healthy.

5. Monitor Growth
Within 5–7 days, the culture should turn visibly green and slightly thicker. A healthy culture smells fresh, not rotten or sulfuric.

6. Harvest
Harvest using a fine mesh sieve or by decanting. Refrigerate unused portions and keep backup cultures running to avoid crashes.

Tips for Success

• Tetraselmis is motile—strong aeration prevents it from settling.

• It’s less tolerant of poor conditions than Nannochloropsis, so cleanliness matters.

• Always sanitize equipment between batches to avoid contamination.

Why Culture Tetraselmis?

• Rich nutrition: EPA, DHA, amino acids

• Boosts pod and rotifer enrichment

• Excellent for larval fish stages

• Improves microfauna health and reproduction

Whether you’re feeding a pod population or enriching live foods, Tetraselmis delivers balanced, complete nutrition in every drop.