Chlorella is one of the easiest and most versatile freshwater microalgae you can culture at home. Whether you're feeding Daphnia, enriching scuds, boosting shrimp tank biofilm, or conditioning live foods, this complete care guide will show you exactly how to use and culture Chlorella successfully.
What Is Chlorella Microalgae?
Chlorella is a single‑cell green freshwater microalgae used in aquariums as a live food, water conditioner, and microfauna booster. It’s nutrient‑dense, easy to use, and ideal for feeding Daphnia, scuds, copepods, shrimp, snails, and other freshwater organisms.
Aquarists use Chlorella for:
- feeding Daphnia cultures
- feeding scuds (Gammarus)
- supporting copepods and microfauna
- enriching live foods before feeding fish
- improving water quality in nano tanks
- boosting biofilm for shrimp and snail
How to Use Chlorella in Freshwater Aquariums
Chlorella is one of the most widely used microalgae for freshwater systems. It provides nutrition, supports microfauna, and helps stabilize small tanks.
Best Uses in Freshwater
- Feeding Daphnia
- Feeding scuds
- Feeding copepods
- Feeding shrimp and snails
- Conditioning live foods before feeding fish
- Supporting biofilm growth
How Much to Use
- Add enough to tint the water light green
- Feed again when the water clears
- Start small — you can always add more
How to Feed Chlorella to Microfauna
Daphnia
Tint water light green; feed again when clear.
Scuds
Add a small amount to cloud the water; they graze on suspended cells and biofilm.
Copepods
Use small daily feedings; Chlorella is an excellent primary food source.
Shrimp & Snails
Provides supplemental nutrition and boosts biofilm.
How to Store Chlorella
- Keep refrigerated (not frozen)
- Shake gently every few days
- Use within 4–6 weeks for best results
- If it smells foul or separates strangely, discard
How to Tell If You’re Feeding the Right Amount
- Water clears within 24–48 hours → perfect
- Water stays green for days → too much
- Water turns cloudy or smells bad → reduce feeding
Ready to start your own culture? Get live Chlorella HERE!
How to Culture Your Own Chlorella at Home (Simple Step‑by‑Step Guide)
Culturing Chlorella at home is easy and a great way to maintain a steady supply of live microalgae for Daphnia, scuds, copepods, shrimp, and snails.
What You Need
- A clean, sterile bottle or jar (16–32 oz)
- Your starter Chlorella culture
- Freshwater (dechlorinated)
- A light source (LED light or grow light)
- Fertilizer such as f2
- Gentle aeration
Step‑by‑Step Instructions
- Fill your container with clean, dechlorinated water.
- Add your starter culture (10–40% of the total volume).
- Add fertilizer if desired (follow product instructions).
- Provide light for 12–16 hours per day.
- Add gentle aeration to keep cells suspended and oxygenated.
- Let it grow — the culture should darken over 5–7 days.
- Harvest when dark green by pouring off up to 50% of the culture.
- Top back up with fresh water and continue the cycle.
How to Tell When Your Culture Is Ready
- Pale green → still growing
- Medium green → usable
- Dark green → ready to harvest
- Brown or clear → culture crash (restart with backup)
How Often to Split or Harvest
- Most hobbyists harvest every 5–7 days
- Never harvest more than 50% at once
- Always keep a backup bottle growing separately
Tips for Success
- Keep the culture warm (70–78°F)
- Avoid direct sunlight
- Shake gently if cells settle
- Use clean, sterile equipment to avoid contamination
- When adding new water, try and match temperature to reduce osmotic shock
Troubleshooting Chlorella Use
Water smells bad
- You’re overfeeding. Reduce the amount and increase water changes.
Water stays green too long
- Use smaller doses.
Daphnia or scuds aren’t responding
- Feed less at a time; they may be overwhelmed.
Culture looks separated or stringy
- Swirl gently; if it doesn’t mix, it may be expired.
Chlorella FAQ — Answers to Common Questions
Is Chlorella safe for freshwater tanks?
Yes — it’s one of the best microalgae for freshwater microfauna.
Does Chlorella survive in freshwater?
Yes — unlike Tetraselmis, Chlorella is naturally freshwater.
Can Chlorella cause algae blooms?
Only if massively overdosed. Normal feeding is safe.
How often should I feed Chlorella?
Feed again when the water clears — usually every 1–3 days.
How long does Chlorella last in the fridge?
4–6 weeks when stored properly.
Can I use Chlorella to culture Daphnia?
Yes — it’s one of the best foods for Daphnia cultures.
Can I use Chlorella to feed scuds?
Yes — scuds graze on suspended cells and biofilm.
Is Chlorella good for shrimp?
Yes — it boosts biofilm and provides supplemental nutrition.
Can I mix Chlorella with Tetraselmis?
Yes — many aquarists use both for a broader nutrient profile.
Does Chlorella need to be shaken before use?
Yes — cells settle naturally; shake gently to resuspend.
Can I overdose Chlorella?
Yes. Too much can cause cloudy water or oxygen drops. Start small.
Why is my Chlorella separating in the bottle?
It’s normal for cells to settle. Shake gently. If it won’t mix, it may be expired.
Can I freeze Chlorella?
No — freezing kills the cells and ruins the culture.
Is Chlorella better than Tetraselmis?
They serve different purposes. Many aquarists use both.
Can I culture Chlorella without aeration?
Yes — but growth will be slower. Aeration improves results.
Why did my Chlorella culture crash?
Common causes include contamination, lack of light, or old culture age.