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🧫 Launching soon · built by two reefers

Live food and biology your reef actually needs.

Live phytoplankton, live copepods, and seeded ceramic bio media — cultured and seeded in small batches, not mass-produced. Everything you need to feed the food web and jumpstart your filtration.

What we make

Cultured & seeded, not mass-produced.

We're starting with three things every reef tank needs: food for the bottom of the food web, and biology to jumpstart your filtration. All three are currently being farmed for our first batches.

New to reef biology? Read our guide on why copepods, live phytoplankton & seeded media matter →

Why ReefDen

Designed by a reefer, not a spec sheet.

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Tested in a real reef

Every batch is checked in our own tanks before it ever ships — density, color, and cell or bacterial health.

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Small-batch cultured

Grown, bottled, and seeded fresh in small batches — not diluted, not sitting on a shelf for months.

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Live, not preserved

Actively growing cells and bacteria, not freeze-dried powder or a sterile scaffold.

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Shipped to arrive alive

Packed cold or damp depending on what's inside. Because a dead culture doesn't feed or seed anything.

Our story

Two reefers, five years, and a lot of broken gear.

ReefDen is two friends who met the way a lot of reefers do — geeking out over frags and bickering about alkalinity at the local fish store. Five years later, we've talked each other into (and out of) more tanks than we'll admit, traded a reef's worth of corals, and bailed each other out of every classic disaster: ich scares, a heater stuck "on," and the occasional 2 a.m. "why is everything closed up?!" panic text.

Between us we run two very different reefs and think in two very different ways — one of us lives in CAD and calipers, the other can't stop rescaping rock and chasing the next acro. Turns out that's the perfect team for building gear: one obsesses over the millimeter, the other over whether corals actually thrive on it.

ReefDen began with a wobbly frag rack and a $30 part that took three weeks to ship. We were sure we could make something that actually fit — so we did. Printed it, dropped it in the tank, watched it float (oops), fixed it, and printed it again. These days we're focused on reef biology and nutrition instead — but every product still earns its place the same way: tested and reef-proven in our own tanks before it ever reaches yours.

Run your reef. We'll handle the food.
"Two reefers who'd rather fix the problem than live with it."
5 yrsfriends in the hobby
2reef tanks (our test labs)
1caliper we fight over
frags traded & lost