Clownfish

Breeding Clownfish

By Rick Martin

First learn to sex them... which is quite an interesting pursuit when it comes to clownfish. In a group the female is the largest, with the male as the second largest. All others will be juveniles and gender-neutral. When one of the adults disappears, the next biggest will take its place. Thus the male will become female and a juvenile will turn into a male. Once they are female they cannot change again. In certain species there are physical differences but it's not a real good idea to rely on this as they may have changed sexes but not markings.

Buying an established pair is perhaps the easiest way to go. Many aquarium/fish stores have these or can order them for you. Sometimes you get lucky and get a pair already spawning. Look for a pair that hangs out together as this is a good sign that they are a true pair. Another possibility is buying a group of juveniles and raising them to breeding age.

This takes a good deal longer as some species take quite a while to mature. Also certain species are more aggresive and you may have to remove unwanted extras. Basically, you watch as the group matures and they will pair up by themselves. The female will be the largest, with the male next biggest. The rest should stay juveniles.

The Set-up

The larger species will need a 29-gallon and the smaller a 20-gallon tank.

A clay pot or a piece of ceramic tile is a favorite to spawn on.

A heater.

A light on a timer -- regular day/night cycle is important.

Feeding the Larvae

This takes some preparation and is really beyond the scope of this page. I recommend reading the Plankton Culture Manual from Florida Aqua Farms. Its tells all you need to know and more about raising nannochloropsis oculata, greenwater, and Brachionus sp., rotifers. They also can provide live cultures and starter kits. Rotifers are the first foods and must be fed immediately to the larvae. Depending on the species you'll need to feed them rotifers for the first 3 days to 3 weeks.

The Day of Hatching

When the eggs are first laid they are a bright orange. After a couple of days the color fades and eyes appear. The male guards the nest and fans the eggs to keep them oxygenated. Depending on the temperature, around day 8 the eyes will become silver. This means its time to hatch.

At this point you must decide to stay up after the lights go out and catch the larvae or move the eggs to the larvae tank. If you decide to leave them with the parents to hatch you can shine a flashlight in the corner of the tank. The larvae are attracted to the light and then you can either syphon the larvae out or scoop them out with a ladle. If you move them you must keep the eggs aerated gently with a airstone or fungus will set in.

The Larvae Tank

A simple 5 or 10 gallon tank works fine for a larvae tank. Add a heater and an airstone and you're set. No real biological filtration is usually provided. I have used live rock, but there's always a chance of bacteria infection coming from it. Ammonia needs to be monitored. Adding Amquel or its equivalent when traces show up have been beneficial. Having a bare bottom makes it easier to clean. You may need to leave a light on the first few until the larvae develop their hunting skills.

The first 10 days are the most crucial. This is the period when the greatest number are lost. For some reason metamorphosis (around day 10) is very stressful. Immediately following this transition stage, the youngsters will begin developing their stripes... after which point you're pretty much home free. And free to enjoy your beautiful little clowns! Good luck!

Three day old clownfish egg. The "stalk" at the base of the egg is actually the tuft of adhesive filaments that held the egg onto the rock that served as the spawning site.

Photo by Bill Capman

Clownfish Care:

Clownfish and Damselfish are the only species of fish which can avoid the stings of an anemone, which can be quite potent. The exact mechanism by which this is accomplished is the subject of debate

Clownfish in an aquarium environment can exist very well without an anemone (this may be advisable as most anemones are extremely difficult to keep alive even for experienced aquarists).

Coral Reef Related Articles:

True Percula Clownfish. It can be found individually, or more commonly, in pairs or small groups within the same anemone such as Heteractis magnifica or Stichodactyla mertensii.

Sea Anemone: The long tentacles are equipped with stinging cells that paralyze prey. Anemones required excellent water conditions, moderate to strong current and intense lighting. A minimum light intensity of 10,000 lux is indispensable for them to survive and grow.

Coral Reef: Although corals are often mistaken for rocks or plants, they are actually composed of tiny, fragile animals called polyps. A polyp is a spineless animal. Polyps can be the size of a pinhead while others are larger, sometimes a foot in diameter. One coral branch is covered by thousands of these animals.

Maroon Clownfish. Do not move the Maroon Clownfish with a net as its cheekspines will become entangled. Use a specimen container if capture is necessary.

Tomato Clownfish. Coming from the Pacific Ocean this species can become very aggressive with age, however if you can buy a match pair, at the same time, they will often live together in harmony. It can be an excellent choice for the beginner since is very hardy and can live without an anemone.