Green Water Starter Culture

About this culture

Green water is pea-soup water turned green by free-floating algae — the food daphnia and moina cultures run best on, and a gentle first graze for many newly free-swimming fry. A 250 ml starter seeds a sunlit bucket or dedicated tub; under South African sun a bloom builds in days, and from then on you harvest into your moina culture whenever the water clears. Overseas guides make this sound hard because their summers are short — ours are not. Out of stock for now: tap Notify me and we will WhatsApp you the moment the next batch is ready.

Best for

• Feeding daphnia & moina cultures
• First graze for tiny fry
• Breeders who want a dedicated food tub
• Anyone tired of yeast-only moina cultures

How to culture it

1. Tip the 250 ml starter into a light-coloured bucket or tub of aged / old tank water and stand it in full sun (Cape summer: tint in 3–5 days, soup within two weeks).
2. Optional: a pinch of liquid plant food or a small piece of lettuce (removed before it rots) speeds the bloom — go easy, or you get a bacterial swamp instead of green water.
3. Keep one dedicated green-water tub on a harvest-and-refill rhythm so the moina culture always has food. Shade cloth keeps birds and dust out; never spray insecticide near it.
4. Cape winter: outdoor blooms slow — bring a small bottle or tub onto a sunny windowsill so the food line survives until spring, exactly as you would a backup culture.

How to feed it

Add green water to the daphnia/moina tub until the water takes a faint green tint — then stop. Feed again when it clears.

Visible green = food present; clear = feed; milky-white = bacterial bloom (water-change, feed less, wait). Many fry also graze the algae directly in the first days.

Go deeper: How to culture green water from a starter →