The carpet anemone (Stichodactyla — Haddon's S. haddoni and the giant S. gigantea) is the biggest, most dramatic host anemone in the hobby, and the most dangerous. Its short, dense tentacles work like fly-paper: anything that touches the disc sticks, and the anemone can catch and eat fish — bottom-dwellers, tangs that rest on it, even a clownfish that isn't properly bonded to it. It's a deep-sand animal for a large, mature, brightly-lit tank, and it's expert-only — with S. gigantea notoriously high-mortality.
Care at a glance
| Adult size | Big — commonly ~1–2 ft across, and exceptional Haddon's carpets approach 3 ft. (A mini/“maxi-mini” carpet, S. tapetum, stays 4–6 in.) |
|---|---|
| Lifespan | Not well documented — anemones can be very long-lived when healthy, but no reliable captive figure exists, so don't count on a set number. |
| Minimum tank | ~30 gallons is the absolute floor for Haddon's; a large, mature system is strongly preferred given the adult size and the deep sand bed it needs. |
| Lighting | High — roughly PAR 200–300+ for Haddon's (a mini carpet takes ~150–250). Photosynthetic, so bright, stable light is essential. |
| Water flow | Low-to-moderate, gentle turbulent flow; cut the flow right down while it settles and acclimates. |
| Placement | A SAND-dweller — Haddon's buries its foot in a deep 3–5 in sand bed (the giant carpet anchors to solid material set within the sand). Place it BEFORE other livestock, and screen every pump: a wandering carpet in a powerhead can rupture and crash the tank. |
| Temperature | ~75–82°F (24–28°C) — stability matters more than the exact set-point. |
| pH | 8.1–8.4. |
| Specific gravity | 1.023–1.025. |
| Other targets | dKH ~8–12; zero copper, as with any invert. |
| Feeding | Photosynthetic PLUS an aggressive meaty eater — spot-feed mysis, brine, chopped shrimp/clam/mussel or silversides cut smaller than the mouth, roughly 1–3× a week. Don't overfeed. |
| Temperament | Extremely powerful, sticky sting — it is a genuine predator that catches and eats fish, and it's one of the few anemones that can sting a human. A large, stressed one can discharge and harm the whole tank. |
| Reef-safe | No — not reliably reef-safe. Its potent sting harms corals and other anemones, and it eats fish and inverts. Treat it as a species-display animal, not a mixed-reef citizen. |
| Natural range | Indo-Pacific (and Red Sea). |
The fish store gets these wrong
Common myths, kindly corrected — no shame for having believed them.
- “Add a clownfish and it's safe.” False — a non-bonded or weak clown can be caught and eaten. Hosting is species-specific and never guaranteed.
- “It's reef-safe like a coral.” No — its potent, wandering sting and fish/invert predation make it unsafe for a mixed reef.
- “Gigantea and haddoni are interchangeable.” No — the giant carpet is far higher-mortality; if you must keep a carpet, start with Haddon's, never gigantea.
- “It'll sit where I put it.” It buries its foot but can still wander — an unscreened powerhead is a classic, avoidable disaster.
Before you buy
- Expert-level experience and, ideally, a species tank — this animal eats fish.
- A deep (3–5 in) soft sand bed and a large, mature, brightly-lit system.
- The right species: choose S. haddoni over the high-mortality S. gigantea.
- Every powerhead and overflow screened before it goes in.
- A healthy, well-coloured, firmly-attached specimen — poor imports fade away.
Signs something's wrong
A struggling invert is usually telling you about water quality, acclimation, or (for shrimp and crabs) a fresh moult — here's what to watch for:
- Mouth gaping open and staying open — distress.
- Bleaching or going pale — zooxanthellae loss; a badly bleached carpet often won't recover.
- Slowly shrinking and “fading away” — the classic giant-carpet decline.
- Won't eat, spits food, or shows mushy/disintegrating tissue — often a transit infection; and a detached, drifting foot is heading for a pump.
Work through the Carpet Anemone trouble card — the water, light, flow and pest checks that fix almost every struggling invert.
Never
- Never keep one with small or bottom-dwelling fish you value — the sticky disc catches and eats them.
- Never assume a clownfish is safe with it — a mismatched or weak clown can be eaten.
- Never start with a giant carpet (S. gigantea) — it's high-mortality; choose Haddon's.
- Never run unguarded powerheads — a wandering carpet that ruptures can crash the tank.
- Never keep it over a shallow/bare bottom, or add it to an immature tank.
Common carpet anemone questions
Can a carpet anemone really eat a fish?
Yes. Its short, dense tentacles work like fly-paper — any fish that touches the disc sticks fast and gets consumed. Bottom-dwellers, tangs that rest on it, and even a mismatched clownfish are all at risk. This is the number-one reason it isn't a casual reef pet.
Will a carpet anemone eat the clownfish I bought to host it?
It can. Only a properly bonded, compatible clown is reasonably safe; a non-matched or weak clownfish can be caught and eaten. Never assume the pairing will just work.
Should I get a giant carpet (gigantea) or a Haddon's carpet?
Haddon's (S. haddoni). The giant carpet (S. gigantea) is notoriously high-mortality — hard to acclimate and prone to slowly fading away. Even Haddon's is expert-level, but it's far more forgiving.
Does a carpet anemone go on sand or rock?
Sand. Haddon's buries its foot in a deep 3–5 inch sand bed; the giant carpet anchors to something solid set within the sand. Give it real depth, and place it before adding other livestock.
How much light and flow does a carpet anemone need?
High light (roughly PAR 200–300+ for Haddon's) and low-to-moderate, gentle turbulent flow — turn the flow right down while it acclimates. It's photosynthetic and also an aggressive meaty eater.
Can a carpet anemone hurt me?
Yes — Haddon's is one of the few anemones whose sting can affect a human, so handle it carefully. And never let one get pulled into a powerhead: a large ruptured carpet can crash the whole tank.
🐚 Did you know? — Carpet Anemone fun facts
Little true delights about the carpet anemone — each one checked against a named source, no reef-store folklore.
- Haddon's carpet anemone is a true giant, spreading its flat sticky disc to roughly 50 to 80 centimetres across. Wikipedia
- It shares its home with six different species of clownfish, and its carpet even shelters porcelain crabs and tiny sexy shrimp. Wikipedia
- Beneath its velvety appearance, its tentacles immobilise small prey using potent natural toxins. Wikipedia
Sources & further reading
This guide was written and fact-checked against these authorities. It's honest, general guidance — not a diagnosis, and not a substitute for an aquatic vet or your own test kit:
- Tropical Fish Hobbyist — The Carpet Anemones — haddoni vs gigantea size/placement (sand-buried foot), photosynthetic + carnivorous feeding, fly-paper sting & fish predation, clown host lists, pH 8–8.4, warning signs, place before other livestock
- Reef Chasers — Haddoni Carpet Anemone Care Guide — PAR 200–300, low-moderate flow (kill flow to acclimate), 3–5 in sand bed, temp 82°F (77–84), pH 8.0–8.4, EXPERT, "wipe out whole tank" sting warning, Indo-Pacific
- LiveAquaria — Haddon's Carpet Anemone — size up to 3 ft, min tank 30 gal, SG 1.023–1.025, temp 72–78°F, dKH 8–12, pH 8.1–8.4, High light/Medium flow, Difficult, Aggressive, reef-safe with caution, clown host list
- AquariumBreeder — Proper Care for Carpet Anemones — min tank 50 gal, feeding 2–4×/wk, temp 75–82°F, SG 1.023–1.025, pH 8.1–8.4, oral-disc sizes, eats non-compatible clownfish and bottom-dwelling fish
Written and fact-checked by The Coralkin Team against marine-aquarist sources — if your carpet anemone is struggling, it's almost always water quality, acclimation or a moult — check those first and ask an experienced reefer. We never guess a care number.
🔬 Review status: team-written and fact-checked against cited sources · not yet reviewed by a marine vet. How we research & fact-check →
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