Pyrocystis lunula  

(literally, moon-shaped fire cell - cool, huh?)

These bioluminescent dinoflagellates (we just call them “dinos”) are single-celled marine algae. They live from sunlight during the day, and give off visible light when disturbed at night.

Your dinos will be happiest in a spot that is well-lit but not too warm (no direct sunlight). They will only glow at night, and they’re brightest 2-4 hours after dark, so you may want to place them in your bedroom, where you can say hello to them before getting into bed.

Let your eyes adapt to the dark for a few minutes, then rock the dinos gently back and forth to make them light up. You’ll be able to see the single cells as they flash in response.

Your pet dinos should be ok in the salt water medium they came in for a couple of weeks or months. You can grow a fresh batch by pouring them into a bottle of seawater with some additional nutrients. If you want to keep them growing, this should be done every 3-4 weeks. Add one part of the old culture to 3-4 part salt water with nutrients. You can get salt water at your local aquarium store for a few bucks per gallon. Sea water (and the salt water at some aquarium stores) may contain other algae that can easily outcompete your dinos though. So if you start with sea water, it’s safest to boil it for a few minutes and let it cool to room temperature. Or do what I do, and buy distilled water and add “Instant Ocean” salt, available at your local aquarium store (to a density of 1.020, or 20 grams of salt per liter of water).

For additional nutrients, we’ve tried a number of different plant fertilizers to try mimic the effect of the “professional” mix:

- Miracle Gro Liquid Houseplant Food (15 drops per liter of salt water)

- Miracle Gro Water Soluble All Purpose Plant Food (2.5 mg per liter)

- Alaska Fish Fertilizer 5-1-1 (1/10th of a drop per liter)

The amounts given here are just a suggestion - experiment and let us know what works! You can also buy the additional nutrients online here:

Or buy the growth medium (salt water + nutrients) here:

Since the dinos live by photosynthesis, they do need access to some CO2. Just like other algae and plants, they use CO2 as their carbon source, and produce O2 in the process. However, they grow slow enough that they can go for a long time with the cap on. If you grow them in a bottle, you may want to blow in the bottle when you say hi to them at night, to give them some extra CO2 from your breath.

For more information:

If you would like to learn more about bioluminescence, and maybe tinker with engineering bioluminescent bacteria, let us know - we are considering starting up a BioLuminescence Community Project at Counter Culture Labs. No membership required!

If you have any questions, feedback on how your dinos are doing, or suggestions for how to improve this page, feel free to contact