How to Spawn and Raise Amphiprion ocellaris Larvae

We often hear from hobbyists who are curious about breeding marine fish at home. While breeding species like Yellow Tangs isn’t possible in a home aquarium, there are several beginner-friendly options to get started - clownfish, seahorses, and Banggai Cardinalfish. In this article, we’ll focus on one of the most popular and rewarding choices: Amphiprion ocellaris, the common clownfish.

At The Biota Group, we believe ethically bred captive bred fish are hardier, healthier, and reduce pressure on wild populations. Clownfish are among the most recognizable and beloved marine fish, and their ability to be easily captive bred played a crucial role in the early days of marine fish breeding. Clownfish are arguably the easiest marine fish to breed in home aquariums. If you’re interested in spawning and raising marine fish, clownfish are one of the best fish to start with because they are easy and inexpensive to raise, and don’t require a lot of space. 

Setting Up a Clownfish Breeding Pair

Clownfish are sequential protandrous hermaphrodites, meaning juveniles change sex when the dominant fish in the group are lost. In the wild, clownfish live in small groups within anemones, where the largest fish is the dominant female, the second-largest is the male, and the rest are non-breeding juveniles. If you start with two juveniles, they will naturally form a pair, with one transitioning into a female over time.

For breeding, choose:

• A healthy, bonded pair (purchased as a pair or formed from juveniles)
• Captive bred clownfish (more adaptable and easier to breed)
• Clownfish with good body condition and shape - no underbite/overbite, bent spine, short body, or other deformities

This clownfish bred in 2009 by an unknown breeder has a beautiful pattern but slight deformities.

Tank Setup for Breeding

Ideally you will have some tank setup and reefkeeping experience before setting up your Clownfish breeding aquarium. Understand the Nitrogen cycle, proper quarantine, and cycling a new aquarium well before beginning.

• Tank Size: A 20–30 gallon tank is sufficient for a breeding pair.
• Filtration: Use a sponge filter or gentle filtration to avoid harming eggs and larvae.
• Hiding Spots: Provide a clay pot, ceramic tile, or flat rock as a spawning surface.
• Anemone (Optional): Clownfish will spawn without an anemone, but having one may encourage natural behavior. 

Encouraging Spawning

Clownfish maturity determines when they'll be able to spawn. It can take a year or two after putting two juvenile clownfish together for them to spawn. An already established male/female pair can spawn much more quickly.

Once your pair is established and mature, encourage spawning with:

• Stable Water Parameters: Keep temperature 77 - 80°F, salinity 1.023 - 1.026, and pH 8.0 - 8.3.
• Keeping the tank clean: Clean and siphon detritus from the tank regularly, ideally before and one hour after each feeding
• High-Quality Diet: Feed often, a mix of frozen mysis, enriched brine shrimp, Easy Reefs DKI pellets, and Masstick to condition the pair. Soak foods in a Highly Unsaturated Fatty Acid supplement and vitamins for best results. A poor broodstock diet will result in low quality eggs and larvae!
• Consistent Lighting: Maintain a regular light cycle (12 hours on, 12 hours off) to regulate spawning behavior.

Keep notes on when your clownfish spawn. Clownfish tend to spawn on a fairly regular schedule about once every two weeks. If you can predict each spawn date, you can better prepare for the larvae.

Spawning Behavior

• The pair will clean a spawning site on a surface such as the inside of a clay flowerpot.
• The female lays hundreds of orange eggs, and the male fertilizes and fans them to provide oxygen.
• Eggs typically hatch in 7 - 8 days, usually at night.

Preparing for Hatch Night

Before hatching, set up a separate larval rearing tank:

• Tank Size: A small 5 - 10 gallon tank works best.
• Blackout Sides: Darkening or painting the sides, back, and bottom of the tank black keeps larvae focused on food. Krylon paint when dry is safe for fish, but do not use mold-resistant paints.
• Gentle Airflow: Use an air stone with fine bubbles to create gentle water movement.
• No Filtration Initially: Larvae are extremely delicate; filtration can be added later.
• Monitor the eggs! Just before hatching, the eggs turn silvery, indicating the larvae are ready to emerge.

Hatching the Larvae

On hatch night, turn off all pumps and use a dim flashlight to attract the larvae.
Transfer the larvae to the rearing tank using a gentle scoop or siphon. Do not expose them to air; this can damage their delicate swim bladders.

First Feeding (Day 1–10)

Larvae require live food to survive, as they cannot eat dry or frozen foods at this stage.

• Live Rotifers:  Enriched with phytoplankton (e.g., Easy Reefs EasyRoti) for better nutrition.
• Greenwater Technique: Adding phytoplankton to the rearing tank keeps rotifers nutritious and stabilizes water quality.
• Light 24/7:  Keep dim lighting on at all times to help larvae find food.
  
• Pro Tip: Growing successful Rotifer cultures takes time, patience, and practice. Don't give up! Click the EasyRoti picture for more details:

Metamorphosis (Day 10–20)

• Around Day 10, larvae begin to develop clownfish colors and stripes.
• Introduce baby brine shrimp and wean onto prepared foods like hatchery pellets and finely crushed flakes.
  

Juvenile Stage (3+ Weeks)

• At around Day 20, the young clownfish resemble mini adults.
• Transfer them to a grow-out tank with gentle filtration.
• Continue feeding a varied diet of frozen, live foods, and pellets like TDO B2 and Easy Reefs DKI pellets depending on fish size.

Common Challenges & Solutions

Poor Hatch Rates?

• Ensure proper oxygenation. The male should be fanning the eggs constantly.
• Avoid handling eggs too much. Let them hatch naturally.
• Check for fungus and remove dead or unfertilized eggs.

Sadly these clownfish eggs were handled too much just before hatching - a reefer tried to transfer them to a local friend for raising - but they perished. 

Larvae Not Eating?

• Make sure rotifers are dense enough. They should be constantly visible.
• Enrich rotifers with phytoplankton or Selcon for higher survival rates.
• Maintain a gentle current so food stays suspended.

High Mortality During Metamorphosis?

• Keep water pristine with regular small daily water changes.
• Siphon organic matter from the aquarium with an airline tube before and one hour after each feeding.
• Avoid sudden changes in salinity, temperature, or light intensity.
• Ensure rotifers and newly hatched brine shrimp are available.

Artemia Shock

Clownfish larvae can experience sudden mortality or "shock" when fed Artemia (brine shrimp) for too long, especially if they’re fed exclusively Artemia past the early stages of development. 

1. Nutritional Deficiency ("Artemia Shock")

Artemia alone does not meet the full nutritional requirements of growing clownfish larvae and juveniles. It's particularly deficient in essential fatty acids, especially highly unsaturated fatty acids (HUFA) like DHA and EPA, which are critical for grain and eye development, immune system function, and cell membrane integrity.

Over time, larvae raised primarily on Artemia develop nutritional deficiencies, even though they appear to be growing well at first. The sudden die-off often seen is linked to a critical tipping point, where their bodies can no longer sustain normal metabolic functions due to these deficiencies leading to "Artemia shock."

2. Inappropriate Particle Size and Texture

As clownfish larvae grow, their digestive systems become more developed, and Artemia becomes harder to digest and process, especially if it is not enriched with phytoplankton like Easy Reefs EasyArt or if the exoskeletons become too tough for small juvenile fish.

3. Oxygen Demand and Water Quality Issues

Artemia can also contribute to biofouling and oxygen depletion in rearing tanks if not consumed quickly. Excess Artemia in the water breaks down rapidly and pollutes the environment, further stressing larvae.

4. Lack of Dietary Transition

In successful hatcheries, larvae gradually transition from rotifers and Artemia to more diverse, nutritionally rich diets (e.g., enriched Artemia, copepods, micro pellets, frozen calanus, etc.). If this transition doesn't happen and they're stuck on Artemia too long, it contributes to developmental issues.

Solution:

• Begin introducing weaning foods (like micro pellets or frozen foods) early!!!
• Transition to a mixed diet as soon as the larvae are large enough to accept other feeds.
• Enrich Artemia before feeding (with Easy Reefs EasyArt, Selco, etc.)

What to do with all these baby Clownfish?!

1. Share or Gift Them

Give them to friends or fellow reefers in your local reef club or aquarium community. It’s a great way to share the joy and promote captive-bred fish.

2. Sell or Trade Locally

Offer them for sale at local fish stores (LFS). Many stores are happy to support local breeders, especially if your fish are healthy and eating well. Trade them for coral frags, equipment, or other livestock with hobbyists or stores. Once you have consistent success, you could sell to other hobbyists at reef swap events.

3. Use Them to Continue Breeding Projects

Select your healthiest individuals to start new breeding pairs. Work on selective breeding goals: color morphs, health, temperament, etc.

Why Choose Captive-Bred Clownfish?

By supporting aquaculture, you’re helping preserve natural reef ecosystems while enjoying some of the most vibrant, hardy, and personality-filled fish available.

If you’re looking for high-quality, captive-bred clownfish, check out The Biota Group’s collection at shop.thebiotagroup.com!