Ask any marine hatchery manager what limits their larval production and the answer is rarely the fish. It is the rotifers — and behind every stable, dense rotifer culture there is a reliable feed. Super Fresh Chlorella V12 (SV12) is our answer to that problem: a live, liquid chlorella concentrate developed specifically for rotifer cultivation, grown in Japan and flown to hatcheries under cold chain.
This article collects everything we are asked about SV12 in one place: what chlorella actually is, where and how SV12 is produced, its full nutritional specification, and the feeding protocol we recommend.
What is chlorella, really?
Chlorella is a single-celled green microalga, near-spherical and only a few micrometres across — in the same size range as a red blood cell. It was first described in 1890 by the Dutch microbiologist M.W. Beijerinck, and about 20 species are known today, each with many strains that differ in form and nutritional content.
Two things make chlorella remarkable as a feed organism:
- It multiplies extraordinarily fast. Under photosynthesis a chlorella cell completes four divisions in about 20 hours, where ordinary dividing cells manage two. A culture pool can be harvested on a rhythm few other feed organisms sustain.
- It sits at the base of the marine hatchery food chain. Rotifers graze on chlorella, and fish larvae eat the rotifers. Around 70 farmed species — including red sea bream, flounder, tiger puffer and tuna — are reared on rotifers fed with chlorella. The alga most larval fish never see is still the foundation of their first weeks of life.
Grown in Chikugo, shipped fresh from Japan
SV12 is produced by Chlorella Industry Co., Ltd., the world's pioneering chlorella manufacturer, at its plant in the Chikugo district of Fukuoka prefecture, Japan. The algae grow in open culture pools up to 40 metres across but only 10–15 centimetres deep — a geometry that keeps every cell within reach of full sunlight.
What sets SV12 apart from dried or frozen algae products is what happens after harvest: nothing. The concentrate is never dried and never frozen. It is packed cold into insulated styrene-foam boxes with cold packs and air-freighted directly from Japan, so the cells that arrive at your hatchery are still alive.
What is inside a box of SV12
The headline numbers from the official SV12 specification:
| Parameter | Specification |
|---|---|
| Live cell density | ~13 billion cells/ml |
| Cell size | 3–6 µm |
| Dry net weight | > 135 g/l |
| Vitamin B12 | > 320 µg/l |
| DHA | 17±2% of total fatty acids |
| EPA | > 2% of total fatty acids |
The DHA and EPA matter because marine fry require both, and standard chlorella contains little of either. Each SV12 cell carries DHA, EPA and vitamin B12, which means rotifers grown on SV12 can be fed to fry directly — the separate, delicate enrichment step after rotifer cultivation is no longer necessary. The vitamin B12 supports healthy, stable rotifer reproduction.
Per 100 g of dry net weight, SV12 chlorella is approximately 54.8% protein, 13.2% fat and 24.3% carbohydrate, with a broad amino acid profile and minerals including calcium, magnesium, iron, potassium and phosphorus. The full composition tables — vitamins, amino acids and the fatty acid profile — are in the datasheet linked from the product page.
The feeding protocol: 200 to 1,200 rotifers per millilitre
SV12 is a highly condensed solution, suitable for both high- and low-density rotifer cultivation and stable enough for continuous systems. The suggested cultivation plan from the manufacturer:
| Day | Rotifer density (ind./ml) | SV12 dose (per million rotifers) | Feeding frequency |
|---|---|---|---|
| Start | min. 200 | 5 ml — saturate the tank | First dosage |
| Day 1 | 300 | 2.5 ml | 4–6 times daily |
| Day 2 | 600 | 3–4 ml | 4–6 times daily |
| Day 3 | 1,200 | > 4 ml | 4–6 times daily |
Culture conditions to hold alongside the dosing plan:
- Oxygen saturation above 90%
- Water temperature 25–28 °C
- Harvest 50% of the culture from day 4
Run this way, a culture multiplies roughly six-fold in three days, and the site's own trial reporting has seen up to eight-fold — the results behind our earlier article on boosting rotifer production with fresh chlorella.
What SV12 does to the rotifers themselves
Feed quality shows up in the rotifer, not the feed bottle. Typical post-cultivation analysis of rotifers raised on SV12 shows total lipid at 12.7% of dry weight, with EPA at 4.1%, DPA at 5.8% and DHA at 10.5% of total fatty acids — a fatty-acid load that rotifers fed plain algae or yeast simply do not carry. That is the nutrition your larvae inherit at first feeding.
Storage and handling
SV12 is a living product, and it is handled like one:
- Store refrigerated at 2–6 °C and keep away from direct light
- Never freeze — freezing kills the live cells
- Use within 30 days of the production date
- Turn the container regularly during storage, and shake gently before use so the cells distribute evenly
Getting SV12
We ship SV12 to hatcheries across our markets with the cold chain intact from the Chikugo plant to your receiving dock. If green-water conditioning with a dried product fits your operation better, Emerald Chlorella powder covers that role — but for intensive rotifer culture, live cells win.
Request a quote or the full datasheet on the SV12 product page, or contact our team for a trial plan sized to your rotifer tanks.
