Clownfish & Anemone Symbiosis Keeping Guide

The symbiotic relationship between clownfish and sea anemones is one of the most fascinating partnerships in the marine world. Recreating this relationship in a home aquarium is a rewarding challenge that requires understanding the needs of both organisms. This article covers everything from species selection and introduction techniques to long-term maintenance of this iconic partnership.

Understanding the Symbiosis

In nature, clownfish and anemones share a mutually beneficial relationship. The anemone provides the clownfish with protection from predators through its stinging tentacles, to which the clownfish is immune thanks to a special mucus coating. In return, the clownfish provides the anemone with food scraps, nutrients from its waste, and circulation through its constant swimming. The clownfish's movements also help oxygenate the anemone and may deter anemone-eating predators like butterflyfish.

Choosing Compatible Species

Not all clownfish host in all anemones. Understanding natural pairings increases the chance of a successful bond.

• Ocellaris clownfish (Amphiprion ocellaris): The most popular aquarium clownfish. Naturally hosts in magnificent sea anemone (Heteractis magnifica), giant carpet anemone (Stichodactyla gigantea), and mertens' carpet anemone (Stichodactyla mertensii). In aquariums, they often accept bubble tip anemones as well
• Percula clownfish (Amphiprion percula): Very similar to ocellaris in hosting preferences. Naturally found with magnificent and giant carpet anemones
• Maroon clownfish (Premnas biaculeatus): The largest clownfish species. Exclusively hosts in bubble tip anemones (Entacmaea quadricolor) in the wild
• Tomato clownfish (Amphiprion frenatus): Hosts primarily in bubble tip anemones and occasionally in other species

Recommended Beginner Pairing

The bubble tip anemone (Entacmaea quadricolor) paired with either ocellaris or maroon clownfish is the most beginner-friendly combination. Bubble tip anemones are the hardiest aquarium anemones and are accepted by the widest range of clownfish species.

Anemone Care Requirements

Anemones are more demanding than most corals and require a mature, stable aquarium.

• Tank maturity: The aquarium should be running for at least 6 months (ideally 12 months) before adding an anemone. Stable water parameters are non-negotiable
• Lighting: Anemones contain symbiotic zooxanthellae and require strong lighting. LED fixtures providing at least 200 PAR at the anemone's location are recommended
• Water quality: Ammonia and nitrite must be at 0 ppm. Nitrate should be below 10 ppm. Phosphate below 0.03 ppm. Stable salinity at 1.025–1.026 specific gravity
• Flow: Moderate, indirect flow. Anemones do not like being blasted with strong direct current
• Feeding: Feed 1–2 times per week with small pieces of raw shrimp, fish, or mysis shrimp. The clownfish will also bring food to the anemone

Introduction Process

Adding the Clownfish First

It is generally recommended to establish the clownfish in the tank before introducing the anemone. This gives you time to ensure the clownfish is healthy and eating well.

Adding the Anemone

Drip-acclimate the anemone slowly over 1–2 hours. Place it in a spot with appropriate light and flow, but understand that anemones will move to their preferred location. This can take days or weeks, and the anemone may wander across the tank. Protect pump intakes and overflow boxes with guards to prevent the anemone from being drawn in.

The Bonding Process

Bonding is not guaranteed and cannot be forced. Captive-bred clownfish that have never seen an anemone may take days, weeks, or even months to accept one. Some may never host. Signs of acceptance include the clownfish cautiously touching the tentacles, rubbing against them, and eventually nestling deep within the anemone.

Common Challenges

• Anemone wandering: Anemones move when unhappy with conditions. They may settle near powerheads or in low-light areas. Adjusting lighting and flow often helps
• Clownfish aggression: Clownfish can become territorial once they host an anemone, attacking tankmates or even the keeper's hand
• Anemone splitting: Healthy bubble tip anemones may reproduce by splitting. This is generally a sign of good health
• Stinging corals: Anemones can sting and kill nearby corals. Provide adequate spacing

On BriChoku, you can find captive-bred clownfish from specialist marine breeders. Captive-bred clownfish are hardier, disease-free, and more likely to accept host anemones compared to wild-caught specimens.