Anemone and Clownfish Symbiosis Tank | Species Compatibility and How to Create the Right Environment
A guide to setting up a symbiosis tank with clownfish and anemones. We introduce anemone species compatible with different clownfish types, tank size, and the light intensity and water flow conditions needed.
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A guide to setting up a symbiosis tank with clownfish and anemones. We introduce anemone species compatible with different clownfish types, tank size, and the light intensity and water flow conditions needed.
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The BreederDirect editorial team specializes in care information for animals, covering veterinary care and breeding to deliver beginner-friendly guides.
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The sight of a clownfish hiding among the tentacles of an anemone is one of the most iconic scenes in saltwater aquarium keeping. However, anemone husbandry is more challenging than coral care, and tank failures due to inadequate preparation are common. This article explains how to choose the right species and set up the environment to succeed with symbiosis.
How Clownfish and Anemone Symbiosis Works
Clownfish are not stung by an anemone's nematocysts because a mucus layer on their body acts as a chemical protective barrier that prevents the anemone from firing its stinging cells. When a clownfish first contacts an anemone, it repeats brief touches over time, gradually adapting its mucus to the anemone's needs. This process is called "acclimation behavior" and typically takes hours to days to complete. The symbiotic relationship is mutually beneficial:
Benefit to the clownfish: The anemone's tentacles provide shelter from predators
Benefit to the anemone: The clownfish drops food remnants to nourish it and creates water flow for oxygen by swimming around
In the wild, specific species pairs form symbiotic relationships, but in captivity this can be somewhat more flexible.
Clownfish Species and Compatible Anemones
Compatible anemone species for each clownfish type are as follows:
In the wild: Giant anemone (Stichodactyla gigantea) and Magnificent anemone (Heteractis magnifica); in captivity, often also accepts Bubble-tip anemone (Entacmaea quadricolor)
Most beginner-friendly clownfish
Tomato clownfish (A. frenatus)
Bubble-tip anemone
Good compatibility
Pink skunk clownfish (A. perideraion)
Sebae anemone (Heteractis crispa)
Sebae anemone has relatively high difficulty for long-term care
The Bubble-tip anemone has relatively low husbandry difficulty and is considered the most beginner-friendly anemone. The Giant anemone is large and beautiful but has the highest difficulty level, requiring strong lighting and stable water chemistry.
Tank Environment Requirements
Anemone husbandry requires the following conditions for tank size, lighting, water flow, and water quality:
Tank size: Minimum 60 cm tank (60 L or larger) for Bubble-tip anemone, 90 cm tank (150 L or larger) for Giant anemone
Lighting: LED suitable for corals is required. Sufficient light intensity is needed for the photosynthesis of symbiotic zooxanthellae; aim for approximately 100–250 μmol PAR (strong light similar to levels needed for SPS)
Water flow: Moderate (anemones dislike direct strong current)
Water quality: Specific gravity 1.024–1.026, temperature 24–27°C, ammonia and nitrite 0 ppm, nitrate below 10 ppm ideal
Since anemones are sensitive to changes in water chemistry, keep them in a stable tank. A golden rule is to introduce anemones only after the tank has been established for at least three months or longer, when the water chemistry has stabilized.
The Anemone Movement Problem and Solutions
The most troublesome aspect of anemone keeping is that they "walk." Although anemones seem like sedentary creatures, they will move around the tank if unhappy with their environment. If they drift into a pump intake or overflow, they risk being sucked in and dying. Additionally, if an anemone contacts corals while moving, its nematocysts can damage them.
Solutions include:
Attach sponge guards to pump intake ports
Install mesh covers over overflow pipes
Create a spot where the anemone will want to settle (shape live rock with crevices that encourage the foot disc to attach)
Bubble-tip anemones prefer to wedge their foot disc into rock crevices, so provide rocks with appropriate gaps
If movement is frequent, review your lighting and water flow conditions
Tips for Successful Symbiosis
Several techniques help ensure clownfish and anemone symbiosis succeeds. First, captive-bred (CB) clownfish are often raised without anemones, so they may not enter one even after introduction. In such cases, be patient and give them several days to weeks. In most cases, they will naturally approach the anemone and begin symbiosis. If they persistently refuse, turning off lights at night sometimes encourages clownfish to seek a safe place and enter the anemone. When keeping a clownfish pair, choose an anemone large enough to accommodate both. If a large clownfish enters a small anemone, the anemone may become stressed and weaken. Direct feeding of anemones is only necessary once or twice monthly—simply place a small piece of shrimp or squid on its mouth.
Common Failure Patterns to Avoid in Symbiosis Tanks
Several typical failure patterns occur in symbiosis tanks with anemones and clownfish:
"Introducing anemones to a newly set-up tank": Anemones require even more stable water chemistry than corals, so introduce them only after at least three months, ideally six months or longer, in a mature, established tank.
"Introducing multiple anemones at once": Even anemones of the same species can chemically attack each other upon contact, weakening one of them. Start with one anemone and confirm stable husbandry before considering adding more.
"Choosing an anemone that is too large for your clownfish": When a small clownfish enters a large Giant anemone, the anemone's toxin may be too strong, causing damage to the clownfish. Consider the balance between clownfish body size and anemone size.
Anemone feeding frequency should be only once or twice monthly. Place a small piece of shrimp or squid directly in its mouth (the central opening). Daily feeding causes anemones to grow excessively and monopolize the tank, or leads to indigestion that degrades water quality—keep feeding minimal. Once the anemone has settled stably and the clownfish has begun symbiosis, success in long-term care comes down to dedicated water quality management.
Anemones have extremely long lifespans, and it is not uncommon for them to live over ten years when kept in appropriate conditions. For long-term success, it is crucial to maintain stable water quality and adequate light intensity continuously.
Experience Symbiosis Magic with BreederDirect
Clownfish and anemone symbiosis is a luxury experience—the chance to witness the ocean's mysteries in your own home. On BreederDirect, you can purchase healthy captive-bred clownfish and consult with breeders about anemone species suited for symbiosis and tank setup advice. We also carry designer clownfish with unique patterns, so you can enjoy a one-of-a-kind symbiosis tank.
