QUICK STATS

Care Level: Easy to Moderate
Diet: Omnivore
Temperament: Semi-Aggressive
Reef-Safe: Yes
Venomous/Toxic: No
Approximate Purchase Size: 1.5-3"
Approximate Max Size: Around 5-6"
Recommended Tank Size: 30-40 Gallons or Larger

CLARKII CLOWNFISH

The Clarkii Clownfish (Amphiprion clarkii), also known as Clark’s Anemonefish or the Yellowtail Clownfish, is a hardy and active clownfish species known for its bold personality, strong feeding response, and attractive yellow, brown, black, orange, and white coloration. Color can vary quite a bit depending on age, collection location, sex, stress, and maturity, because apparently even clownfish needed regional editions.

Clarkii Clownfish are generally hardier and more assertive than many designer Ocellaris varieties. They can make excellent reef aquarium fish, but they should be given enough space and appropriate tank mates. They are not tiny decorative accessories. They are small striped homeowners with opinions and a willingness to enforce property lines.

This species does not require an anemone to thrive. It may host in one if available, but it may also choose coral, rockwork, aquarium equipment, a corner, or whatever location makes the least sense visually. Clarkii Clownfish are known to associate with many host anemone species in the wild, but captive specimens can do perfectly well without one.

Clarkii Clownfish are considered reef-safe and should not bother corals or most invertebrates. However, established adults and breeding pairs may become territorial and may defend a chosen area aggressively. Reef-safe, yes. Peace treaty guaranteed, absolutely not.

Note: Image is a representation of what to expect. The fish you receive may vary slightly in size, color, markings, maturity, and overall appearance.

AQUARIUM REQUIREMENTS

AQUARIUM SIZE

A minimum tank size of 30 gallons or larger is recommended for a single Clarkii Clownfish, with 40 gallons or larger preferred for a pair or community setup. This species gets larger and more assertive than many smaller clownfish varieties, so extra space helps reduce aggression and gives tank mates more room to avoid the clownfish’s chosen territory.

While juveniles may seem small and manageable, adult Clarkii Clownfish can reach around 5-6 inches and may become increasingly territorial with age. Cute baby clownfish are just future aquarium politics wearing stripes.

HABITAT RECOMMENDATIONS

Clarkii Clownfish are hardy and adaptable, making them a strong choice for established reef tanks, fish-only systems, and peaceful to semi-aggressive community aquariums.

Aquascaping: Provide live rock, caves, and open swimming space. Clarkii Clownfish often claim one area of the aquarium and defend it like they have a signed lease and a tiny lawyer.

Substrate: Sand, fine aragonite, crushed coral, or bare-bottom systems can all work. This species is flexible and does not require a specific substrate.

Rockwork: Live rock is recommended for shelter, biological filtration, territory, and overall aquarium stability.

Anemone Hosting: An anemone is not required. Clarkii Clownfish can thrive without one, though they may host in an anemone if available. They may also host in coral, rockwork, aquarium equipment, or the least convenient corner in the tank because clownfish treat aquascaping like a suggestion.

Tank Maturity: A cycled, stable aquarium is important. Clarkii Clownfish are hardy, but they should not be added to unstable or immature systems with ammonia or nitrite present.

Tank Cover: A tight-fitting lid is recommended. Clownfish are not the worst jumpers, but startled fish continue to make vertical decisions that cost money.

WATER PARAMETERS

Clarkii Clownfish are generally hardy once established, but they still do best in clean, stable saltwater conditions. “Hardy” means forgiving, not magically immune to whatever chemistry nonsense humans invent in a glass box.

Temperature: 75-80°F
pH Level: 8.1-8.4
Salinity: 1.020-1.026 specific gravity
Ammonia, Nitrite, and Nitrate: Ammonia and nitrite should remain undetectable. Nitrate should be kept as low as reasonably possible, ideally below 20 ppm.
Water Flow: Low to moderate flow is ideal. They can handle typical reef flow but should have calmer areas where they can rest and establish territory.

DIET

Clarkii Clownfish are omnivores and usually accept a wide variety of frozen, prepared, meaty, and algae-based foods. They are generally strong feeders and adapt well to aquarium diets once settled.

PRIMARY DIET

Frozen Food: Offer mysis shrimp, enriched brine shrimp, marine blends, and finely chopped frozen foods. We at Summit City Coral prefer frozen foods such as LRS Reef Frenzy and PE Mysis.

Prepared Omnivore Foods: High-quality marine pellets, flakes, and omnivore blends can help provide a balanced diet. Smaller pellet sizes are best for juveniles.

Algae-Based Foods: Spirulina flakes, marine algae blends, or mixed omnivore foods can be included occasionally for variety.

Small Meaty Foods: Copepods, amphipods, finely chopped marine foods, and other small meaty options can help support natural feeding behavior.

FEEDING FREQUENCY

Feed small amounts 1-2 times per day. Avoid overfeeding, even when the clownfish acts like one missed pellet is a historic betrayal requiring immediate compensation.

COMPATIBILITY

Clarkii Clownfish are semi-aggressive and work best with tank mates that can handle their personality, especially once the clownfish becomes established or forms a pair.

COMMON TANK MATES

Fish: Gobies, blennies, cardinalfish, wrasses, chromis, dwarf angelfish, tangs in larger aquariums, rabbitfish, foxfaces, and other peaceful to semi-aggressive community fish.

Avoid: Very timid fish that may be bullied, tiny passive fish in small aquariums, large predatory fish that may eat them, and aggressive fish that may constantly fight with them.

Other Clownfish: Avoid mixing with other clownfish species unless the aquarium is very large and compatibility is carefully planned. Clarkii Clownfish can become especially territorial with other clownfish.

Same Species: Can be kept singly or as a pair. When pairing clownfish, it is usually best to introduce two juveniles or one larger and one smaller individual to reduce fighting.

Invertebrates: Safe with most cleaner shrimp, hermit crabs, snails, urchins, and other common reef invertebrates.

Coral: Clarkii Clownfish are considered reef-safe and should not eat soft corals, LPS, SPS, zoanthids, mushrooms, clams, or anemones. However, if they choose a coral as a host, their rubbing and nesting behavior may irritate it.

BEHAVIORAL NOTES

Temperament: Semi-aggressive. Usually manageable in properly sized aquariums, but may become territorial once established.

Hardiness: One of the hardier clownfish species and usually adapts well to aquarium life.

Adult Size: Larger than many Ocellaris and Percula clownfish, often reaching around 5-6 inches.

Pairing: Can be kept singly or as a pair. A bonded pair may defend a territory strongly, especially if preparing to spawn.

Hosting Behavior: Does not require an anemone, but may host in one if available. May also host in coral, rockwork, equipment, or a corner chosen specifically to inconvenience photography.

Reef Compatibility: Excellent for reef tanks. They are safe with coral and most invertebrates, though hosting behavior may irritate some corals.

Territoriality: May defend a chosen area aggressively, especially as an adult or part of a bonded pair.

Color Variation: Clarkii Clownfish can vary from yellow and orange to dark brown or black with white bands. Tail color and body darkness may change with age, sex, stress, and location.

Sex Change: Clownfish are protandrous hermaphrodites, meaning the dominant individual becomes female in a pair. Nature apparently saw aquarium stocking charts and chose improvisation.

Jumping: A tight-fitting lid is recommended. Even hardy clownfish are still fish, tragically powered by fish-level judgment.

ACCLIMATION PROCESS

This acclimation method helps reduce stress by gradually introducing the fish to your aquarium’s temperature and water chemistry.

1. TURN OFF THE LIGHTS & ATO

Turn off aquarium lights to reduce stress. If you have an Auto Top Off system, switch it off before starting acclimation.

2. FLOAT THE BAG

Float the sealed bag in the aquarium for 15-20 minutes to allow the temperature in the bag to equalize with the tank.

3. OPEN BAG, ADD FISH TO CONTAINER

Carefully open the bag and transfer the fish and shipping water into a clean bucket or container.

4. ACCLIMATE USING TANK WATER

Add 1/4 cup of tank water to the container every 5 minutes for 40 minutes.

5. TRANSFER FISH TO AQUARIUM

Once acclimation is complete, gently transfer the fish into the aquarium using a net or specimen container. Discard the shipping water. Do not pour shipping water into your aquarium.

6. REFILL THE AQUARIUM WITH SALTWATER

You may need to replace the saltwater removed during acclimation with fresh mixed saltwater.