THE GEAR REAL REEF TANKS RUN ON | TOURS · EQUIPMENT · GUIDES

ALLCORALS REEF TANKS & GEAR

Reef Tank Anemone Guide: Species, Care & Clownfish Hosting

A complete guide to keeping anemones in your reef aquarium — from beginner-friendly Bubble Tips to expert-only Magnificas. Learn which clownfish pair with which anemone, how to meet their demanding care needs, and how to avoid the most common mistakes. Compiled from Bulk Reef Supply, Reef Builders, Reef2Reef, Practical Fishkeeping, and the reef keeping community.

14 min read Sources: 16 expert articles

1. Anemones in the Reef Tank

Sea anemones are among the most captivating animals you can keep in a reef aquarium. Their flowing tentacles, vivid colours, and symbiotic relationship with clownfish make them a centrepiece in many tanks. However, they are also one of the most challenging invertebrates to maintain — they can move around the tank at will, deliver powerful stings to neighbouring corals, and require rock-solid water quality to thrive [1].

Unlike corals, anemones are mobile. They will walk across your aquascape until they find conditions they like, and there is no way to force them to stay in one spot [2]. Along the way they can sting and kill expensive corals, get sucked into powerheads, or clog overflow boxes. This is why most experienced reefers recommend a mature tank of at least 6–12 months before adding any anemone — new tanks lack the biological stability these animals demand [3].

That said, the right species in the right system can be incredibly rewarding. Bubble Tip Anemones (BTAs) have become the gateway species for most hobbyists, while Rock Flower Anemones offer a nano-safe alternative that barely moves at all [4]. At the other end of the spectrum, Magnificent and Carpet anemones are stunningly beautiful but carry a well-earned reputation for being expert-only animals [5].

Fair warning: Anemones can and will sting corals. Their tentacles contain nematocysts (stinging cells) that fire on contact, causing tissue damage to nearby invertebrates. Give them space and accept that they may rearrange your plans. [1]

2. Popular Species Comparison

Data compiled from Bulk Reef Supply [1], Practical Fishkeeping [5], Reef Chasers [6], Reef2Reef [7], and community experience. Prices reflect typical retail in the US hobby market.

Species Scientific Name Max Size Light (PAR) Flow Difficulty Price Range
Bubble Tip (Green/Brown) Entacmaea quadricolor 12″ 150–300 Low–Med Beginner $25–60
Rose Bubble Tip E. quadricolor 12″ 200–350 Low–Med Beginner $40–100
Rainbow BTA E. quadricolor 12″ 200–350 Low–Med Intermediate $150–1,000+
Long Tentacle Macrodactyla doreensis 18″ 200–350 Low–Med Intermediate $40–80
Magnificent / Ritteri Heteractis magnifica 36″+ 300–500 Med–High Expert $80–250
Carpet (Giant/Haddon’s) Stichodactyla spp. 36″+ 300–500 Med–High Expert $100–400
Sebae Heteractis crispa 18″ 200–350 Med Intermediate $30–70
Rock Flower Phymanthus spp. 4–8″ 50–150 Low–Med Beginner $15–60
Best starter anemone: The standard green or brown Bubble Tip Anemone is the most forgiving species in the hobby. It adapts well to a range of lighting intensities, readily hosts most clownfish species, and propagates through splitting when conditions are good. [3] [5]

3. Clownfish Hosting Chart

In the wild, each clownfish species has a limited number of natural host anemones. In captivity, however, clownfish will often adopt substitute hosts — especially tank-raised specimens that have never seen a natural anemone [8]. The table below shows natural hosts (marked with a filled circle) and common captive substitutes (marked with an open circle).

Clownfish BTA Magnificent Carpet Long Tentacle Sebae
Ocellaris A. ocellaris ○ • • ○ •
Percula A. percula ○ • • ○ •
Maroon P. biaculeatus • ○ ○ ○ ○
Tomato A. frenatus • ○ ○ ○ ○
Clarkii A. clarkii • • • • •
Pink Skunk A. perideraion ○ • • • •
Cinnamon A. melanopus • • ○ ○ ○

• = natural host    ○ = common captive substitute    Sources: [8] [9] [10]

Clarkii clownfish are universal: Amphiprion clarkii is the least selective clownfish in the hobby — it will host in virtually every anemone species available, making it the safest bet if you want a guaranteed pairing. [9]
Rock Flower Anemones do NOT host clownfish. They are a Caribbean species, while all clownfish are Indo-Pacific. Clownfish placed with rock flowers may be stung and injured. [4]

4. Tank Requirements

Anemones are far more sensitive to water quality than most corals. A mature, stable system is not optional — it is a prerequisite. Based on recommendations from Bulk Reef Supply [1], Reef Chasers [6], and Reef2Reef [7]:

Tank Maturity & Size

  • Tank running 6+ months minimum before adding an anemone [3]
  • 30 gallon minimum for a single BTA; 75+ gallons for multiples [6]
  • 100+ gallons for Magnificent or Carpet species [7]
  • Rock Flowers: 5 gallons minimum — true nano-safe anemones [4]

Safety Measures

  • Cover all powerheads with foam guards or intake screens [6]
  • Screen or guard overflow boxes — anemones will climb in [2]
  • Avoid bare-bottom tanks — Long Tentacles need sand beds [5]
  • Keep a gap of 6–8″ between anemone and nearest corals [1]

Target Water Parameters

Parameter Target Source
Temperature 76–80°F (24–27°C) [6]
Salinity (SG) 1.024–1.026 [6]
pH 8.0–8.4 [6]
Alkalinity (dKH) 8–11 [6]
Calcium (ppm) 400–450 [6] [7]
Magnesium (ppm) 1250–1400 [6]
Nitrate (ppm) 5–15 [3]
Phosphate (ppm) 0.03–0.10 [3]
Ammonia / Nitrite 0 (undetectable) [7]

Lighting

Most host anemones contain symbiotic zooxanthellae algae that require strong lighting to photosynthesize. Bubble Tips thrive in 150–300 PAR and will adjust their position to find their preferred intensity [3]. Magnificent and Carpet anemones require intense light in the 300–500 PAR range [7]. Rock Flower Anemones are the outlier, doing well under modest 50–150 PAR [4].

Pro tip: Higher PAR tends to enhance bubble formation in BTAs and intensify colours in most species. However, newly acquired anemones should be acclimated to strong light gradually to avoid bleaching. [3]

5. Placement & Movement

Here is the hard truth about anemone placement: they choose their own spot. You can place an anemone where you want it, but it will move to where it wants to be — sometimes within hours, sometimes over weeks [2]. Attempting to glue, wedge, or cage an anemone almost always ends badly.

Why Anemones Walk

Common reasons for an anemone to move from its initial placement [2] [6]:

  • Lighting: Too much or too little light at the current spot — the anemone seeks its preferred PAR level
  • Flow: Direct powerhead blasts or stagnant water — they prefer gentle, indirect current
  • Water quality: Elevated ammonia, nitrite, or unstable parameters trigger roaming
  • Aggression: Being stung by a neighbouring coral or another anemone
  • Stress from acclimation: Newly introduced anemones often wander for days before settling

Placement Tips

1

Start Low-to-Mid Tank

Place the anemone on a rock in the lower half of the tank with moderate light and flow. It will climb higher if it wants more light. [6]

2

Provide Crevices

Anemones anchor their pedal disc (foot) into gaps in the rockwork. Offering a few suitable crevices gives them options and may reduce roaming. [5]

3

Never Glue or Force

Attempting to superglue an anemone’s foot will injure it. If it detaches, it is telling you the conditions are wrong at that spot. [2]

4

Sand-Dwellers Need Sand

Long Tentacle anemones (M. doreensis) naturally bury their foot in sand. Provide a deep sand bed of at least 4″ for them. Carpet anemones also need an expansive sand area alongside hard substrate. [5]

Rock Flowers are the exception. Phymanthus anemones are among the most sedentary species in the hobby — they bury their foot in sand or wedge into rock and typically stay put. This makes them the safest anemone for a mixed reef. [4]

6. Feeding

Anemones get nutrition from two main sources: their symbiotic zooxanthellae (which photosynthesise under light) and direct feeding of meaty foods. In a healthy tank with strong lighting, zooxanthellae can provide the bulk of an anemone’s energy needs, but target feeding significantly improves growth, colour, and readiness to split [3].

Feeding Schedule & Foods

Species Frequency Foods Portion Size
Bubble Tip 1–2×/week Mysis, chopped silverside, krill Pea-sized pieces
Magnificent / Ritteri 2–3×/week Mysis, silverside, raw shrimp Small chunks
Carpet 2–3×/week Silverside, raw shrimp, clam Larger pieces (strong grip)
Long Tentacle 1–2×/week Mysis, chopped silverside Pea-sized pieces
Rock Flower 1×/week Mysis, brine shrimp, small meaty bits Tiny pieces

Feeding Method

Use feeding tongs or a turkey baster to target-feed directly to the anemone’s tentacles. Turn off powerheads briefly so the food is not blown away before the anemone can grab it [3]. The anemone will curl its tentacles around the food and bring it to its oral disc.

Clownfish bonus: Clownfish that host in an anemone will often bring food scraps back to it, providing supplemental nutrition. This natural “delivery service” means hosted anemones sometimes grow faster and colour up better than unhosted ones. [8]

7. Splitting & Propagation

Bubble Tip Anemones are the most prolific splitters in the hobby. Splitting (longitudinal fission) is asexual reproduction where the anemone elongates and divides into two complete individuals [11]. However, not all splits are a sign of good health — understanding the difference matters.

Healthy Split
Signs of thriving conditions
Large size (8–12″), vibrant colour, well-fed, stable params for months. Both halves recover quickly and retain colour. [11] [12]
Stress Split
Survival mechanism
Triggered by water quality issues, recent move, aggression, or equipment injury. Both halves may be pale or shrunken. Frequent splitting in a new tank = something is wrong. [11] [12]

Splitting Timeline

Once an anemone begins to elongate and show signs of splitting, the process typically takes around 5 days to complete, though some split within 24 hours and others stretch it over weeks [12]. The stalk will visibly narrow at the midpoint before tearing apart. Both halves will have a complete oral disc and tentacles.

Post-Split Care

  • Do not feed for 48–72 hours after the split while the wound heals
  • Maintain pristine water quality — run carbon and do a 10% water change [12]
  • Both halves may wander to find new spots — cover powerheads
  • Resume target feeding after 3–4 days with small mysis portions
  • Expect both halves to be smaller; they will regrow to full size over weeks to months
Only BTAs split reliably in captivity. Magnificent, Carpet, Long Tentacle, and Sebae anemones rarely if ever split in home aquariums. If you want to propagate anemones, BTAs are the only practical option. [11]

8. Common Problems

Bleaching (Loss of Colour)

Cause: Expulsion of symbiotic zooxanthellae, usually from excessive light shock during acclimation, prolonged poor water quality, or high temperature. The anemone turns white or transparent. [3]

Fix: Move to lower light, stabilise water parameters, and target feed 2–3× per week with enriched mysis or Reef Roids. Recovery is possible but slow — weeks to months. If the mouth is gaping open, the anemone is likely beyond recovery. [6]

Deflating / Shrinking

Cause: Periodic deflation (every few days) is normal — the anemone expels internal water to refresh itself. Prolonged deflation lasting days combined with a gaping mouth signals illness. [6]

Fix: Check all water parameters, especially ammonia and temperature. If parameters are fine and deflation is brief, no action is needed. Persistent deflation warrants a large water change and carbon dosing.

Wandering Into a Powerhead

Cause: This is the number one killer of anemones in captivity. An unhappy anemone detaches and drifts into an unguarded powerhead, shredding its body and releasing toxins into the tank [2].

Fix: Prevention is everything. Cover every powerhead with a foam pre-filter or intake guard before the anemone enters the tank. Screen overflow intakes. If an anemone is injured by a pump, immediately remove shredded tissue and run activated carbon heavily. [6]

Stinging Corals

Cause: Anemone tentacles contain potent nematocysts. When an anemone moves or grows into contact with corals, it will sting and damage them. Some species (especially Carpets and Magnificents) have tentacles that can kill SPS and LPS on contact. [1]

Fix: Maintain buffer space. Consider keeping the anemone on an isolated rock island. In severe cases, you may need to choose between the anemone and your coral collection. Many reefers run dedicated anemone-only tanks for this reason. [5]

Carpet Anemone Eating Fish

Cause: Carpet anemones (Stichodactyla spp.) have an extremely sticky, powerful sting. Small fish that swim too close become trapped and consumed — including fish you thought were safe. Haddon’s Carpet is notorious for eating fish, shrimp, and even their host clownfish on occasion. [5]

Fix: Only keep Carpet anemones in species-dedicated setups with large, robust fish. Accept that some livestock losses may occur. This is not a mixed-reef-friendly animal. [5]

Anemone Death & Tank Crash

Cause: A dying anemone rapidly decomposes and releases massive amounts of toxins into the water, potentially crashing the entire tank. Large species like Carpets and Magnificents pose the greatest risk. [1]

Fix: Remove a dying anemone immediately. Signs of impending death: prolonged gaping mouth, melting tissue, foul smell, failure to attach. Run heavy carbon, do a 25–50% water change, and increase aeration. [6]

9. Frequently Asked Questions

How long should my tank be running before adding an anemone?

Your tank should be at least 6 months old with stable, established water parameters before adding any anemone [3]. For expert-level species like Magnificent or Carpet anemones, many experienced reefers recommend waiting 12+ months [7]. The tank needs a completed nitrogen cycle, stable alkalinity and calcium, and a mature biological filtration system. Adding an anemone to a new or unstable system almost always results in the animal wandering, bleaching, or dying.

Will my clownfish definitely host an anemone?

Not necessarily. Tank-raised clownfish have never encountered an anemone and may take days, weeks, or even months to recognise one as a host — some never do [8]. Wild-caught clownfish are more likely to host immediately. Pairing matters too: an ocellaris clownfish with a BTA is not a natural pairing, so it may work or may not. For the best odds, match your clownfish species with its natural host anemone (see the hosting chart above). [9]

Can I keep an anemone in a nano tank?

Only Rock Flower Anemones (Phymanthus spp.) are truly nano-safe. They max out at 4–8 inches, stay put, and thrive in tanks as small as 5 gallons [4]. BTAs can technically be kept in a 20–30 gallon tank, but their tendency to move and split makes them risky in small systems — one split and you have two anemones competing for limited space. Magnificent, Carpet, and Long Tentacle anemones are completely unsuitable for nano tanks. [5]

My anemone is moving around the tank. Is something wrong?

Movement is normal behaviour, especially in the first 1–2 weeks after introduction. The anemone is searching for its preferred combination of light, flow, and substrate [2]. However, persistent wandering beyond 2 weeks often signals a problem: unstable water quality, inappropriate lighting, or harassment from tankmates. Check all parameters and ensure powerheads are covered. Once happy, most anemones settle into a spot and stay for months or years. [6]

Why did my BTA lose its bubble tips?

This is one of the most debated topics in reef keeping and there is no single confirmed answer. Bubble Tips often lose their bulbous tips and develop elongated, stringy tentacles instead. Common theories include: too much light, too much flow, lack of regular feeding, and hosting by an aggressive clownfish [3]. Many reefers report that increased target feeding (2–3× weekly) and moderate PAR (150–250) encourage bubble tip formation. Some BTAs never show bubbles regardless of conditions. [6]

Can I keep multiple anemone species in one tank?

It is generally not recommended. Different anemone species will engage in chemical warfare, releasing toxins that stress or kill the other. Even the same species can be aggressive towards clones that originated from a different parent animal [1]. If you want multiple anemones, the safest approach is to keep clones from the same parent BTA, which are genetically identical and tolerate each other well. Rock Flowers are an exception — multiple individuals of different colours coexist peacefully. [4]

References

Every factual claim in this guide is cited to its original source. Click any [n] in the text above to jump here.

  1. Bulk Reef Supply — “Sea Anemones: A How to Guide for Selection, Care and Feeding”
  2. Reef Aquarium — “Keeping Anemones” (anemone movement and placement)
  3. Top Shelf Aquatics — “Bubble Tip Anemone Care Guide: Feeding, Lighting, and More”
  4. Saltwater Aquarium Blog — “Rock Flower Anemone: Care, Lifespan, Compatibility & Feeding”
  5. Practical Fishkeeping — “Keeping Anemones in the Reef Aquarium”
  6. Reef Chasers — “Bubble-Tip Anemone Care Guide”
  7. Reef2Reef — “Heteractis magnifica Anemone Care and Considerations”
  8. Indoor Ecosystem — “Clownfish and Their Host Anemones”
  9. FishLore — “Clownfish Anemone Compatibility Chart”
  10. Reef2Reef — “Terrific Tentacles: A Beginner’s Look at Anemones for the Reef Aquarium”
  11. Melev’s Reef — “Photo-Documentary of a Bubble Tip Anemone Splitting”
  12. Light.fish — “Anemone Splitting: Causes, Signs & Post-Split Care”
  13. Aquatic Stories — “Why Is My Bubble Tip Anemone Splitting? Good or Bad?”
  14. Aquarium Store Depot — “Bubble Tip Anemone Care Guide: How to Have Real Success With BTAs”
  15. Sunnyside Corals — “Anemone Hosting Clownfish: A Complete Guide”
  16. Reef Builders — “Managing Tissue Necrosis” (anemone death and tank crash risks)

Ready to build your reef?

Browse thousands of coral species from trusted Thai reef shops.

Browse Coral Collection