Live food culturing

How to culture Daphnia (water fleas)

Supplies needed

Live daphnia starter (1-2 cups)
2-5 gallon container or aquarium
Air pump + air stone (gentle)
Yeast (active dry or live phytoplankton)
Light source
Brine shrimp net
No filter (kills daphnia)

Step-by-step

Step 1: Set up culture container2-5 gallon container or unused aquarium. Aged dechlorinated water at 65-72°F. Light source 8-10 hours/day.

Step 2: Inoculate with starterAdd 1-2 cups of live daphnia starter from a hobby breeder or local fishkeeper. Order online (Aquatic Foods, Carolina Biological).

Step 3: Feed 1-2x weeklyTiny pinch of active dry yeast dissolved in water. OR live phytoplankton (Phyto-Feast, Reef Nutrition). Water becomes slightly cloudy, then clears as daphnia eat.

Step 4: Wait 7-10 days for population boomDaphnia reproduce parthenogenetically (no males needed). One female produces 80-100 offspring per cycle.

Step 5: Harvest with brine netSkim daphnia off the surface or scoop from clear water. Rinse in fresh water before feeding to display tank.

Step 6: Maintain cultureNever harvest more than 30% at one time. Add fresh aged water as it evaporates. Resist aerating too vigorously - daphnia are damaged by strong air bubbles.

FAQ

Why did my daphnia culture crash?

Most common: overfeeding (rotting yeast pollutes water), too-strong aeration, bacterial bloom, or temperature spike. Restart with a fresh culture and reduce feeding.

Can daphnia live in my display tank?

They'll be eaten within minutes by most fish. Daphnia are a feeding treat, not a permanent tankmate.

How much daphnia to harvest per fish?

A scoop the size of a dime feeds 1-2 small fish. Adjust based on appetite + tank size.

More live food guides

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Aquarium-keeping fundamentals

Whatever specific topic brought you here, four fundamentals govern long-term aquarium success: water quality, parameter stability, biological filtration, and species-appropriate husbandry. Skip any one and the others struggle to compensate.

Water quality: ammonia + nitrite at zero, nitrate under 30 ppm freshwater + 10 ppm reef. Test weekly with API or Salifert kits. Use our water parameter checker to score your readings against your tank type.

Parameter stability: stable wrong parameters beat fluctuating ideal parameters. Most fish tolerate a wide pH range if it's stable. Sudden swings of 0.4+ pH or 5+°F kill fish faster than chronic suboptimal values. Use temperature controllers (Inkbird) + automated dosing for consistency.

Biological filtration: the bacterial colony on your filter media + rock + substrate is the engine. Never replace all media at once. Use our filter turnover calculator to size correctly.

Species-appropriate husbandry: research adult size, territoriality, diet, and tankmate compatibility before purchase. Use our tank stocking calculator + compatibility guides.

Frequently asked questions

How long does an aquarium take to set up? 4-6 weeks for full cycling + first stocking. Use our cycle ETA calculator + how long does cycling take.

What's the best aquarium for beginners? 20-gallon long. Big enough for parameter stability, small enough for budget + space. See beginner picks.

How often should I do water changes? 25-30% weekly. See water change frequency Q&A + water change calculator.

Why does my fish keep dying? 5 leading causes: uncycled tank, wrong species pairings, no quarantine, undersized tank, neglected water-change schedule. See full diagnosis.