Breeding Clarkii Clownfish
Amphiprion clarkii
The raising Amphiprion clarkii in quantity to 18 days of age using only brine shrimp nauplii is described. Some observations on the keeping of an anemone believed to be Heteractis magnifica (Radianthus anemone) are described. This work was carried out between 1979 and 1981.
Tank and Equipment
A tank having dimensions of 48 inches (long) x 18 inches (deep) x 15 inches (wide) was used. The tank was housed in a cabinet having an overall length of about 54 inches and accommodated a 48-inch north daylight fluorescent tube and a "Grolux" tube of the same length. The fluorescent tubes were shielded from the water by a clear acrylic cover sheet, one quarter of an inch thick. The substrate was a 3:1 (approx.) mixture of aquarium gravel and crushed cockle shell to a depth of 3 to 4 inches, sitting on a home-made under gravel filter. The construction of the filter followed the description in the booklet "The New SeaAquarium System" by Graham F. Cox and was fitted with a one-inch diameter uplift at each end. An airline with a diffuser stone was fed to the bottom of each tube and each was provided with air from a Rena 301 diaphragm pump. Although no measurements were made, it is estimated that the flow from each airlift was not dissimilar to that obtained from a modern power head. Approximately one third of the tank was filled with dead coral skeletons obtained from the beaches of the Seychelles. A piece of slate was placed as a spawning platform adjacent to the host anemone. The water temperature was 78 degrees Fahrenheit No measurements of water quality were carried out although the nitrate level must almost certainly have been very high. Caulerpa prolifera was harvested from time to time and there was light/moderate growth of other algae. No water changes were carried out and tap water was used to replace evaporation losses.
Livestock
In addition to the pair of A. clarkii the following were also present, Paracanthurus hepatus (regal tang), Labroides dimidiatus (cleaner wrasse) and also a Synchiropus picturatus (mandarin goby) for part of the time. The anemone was sited next to the coral skeletons and the A. clarkii made their home in it soon after introduction to the tank. The fish were brought into breeding condition by heavy feeding of frozen lance fish, cockle meat, mysis shrimp and flake food. The anemone was fed twice a week, again on frozen lance fish and cockle meat. On occasions the clownfish would try to remove the food from the anemone and had to be discouraged from doing so using a net handle. The anemone always took the food offered, but on occasions would disgorge it, undigested, about 30 minutes after taking it in.
Spawning
The eggs were always laid on the slate and normally estimated to be about 250 in number. Immediately after spawning was complete, the slate was removed to a separate hatching tank 18 inches x 12 inches x 12 inches. This tank contained only freshly made salt water and an air stone, which was positioned so that a steady stream of air bubbles passed continuously over the eggs. A few drops of methylene blue, to reduce losses due to fungus formation, were added to the water. Despite the addition of methylene blue, some egg losses, estimated at 10-15% always occurred. The eggs hatched after 8 days and were immediately fed newly hatched brine shrimp nauplii. As this is a critical part of the process and their preparation is described under the following separate section.
Feeding
The eggs used were of the "San Francisco Bay" variety. In order to raise the fry, it is essential for the nauplii to be less than 12 hours old, at least for the first 2 or 3 days of feeding. To raise sufficient quantities of nauplii of the required age, the following technique was used. Six glass bottles of 1 pint capacity were half filled with salt water. Each bottle had a stopper with two holes pierced in it. A piece of rigid tubing passed through each of these holes. One piece penetrated the bottle by about an inch while the other reached almost to the bottom. A diaphragm pump fed air, via an airline, through the rigid tubing reaching almost to the bottom of the first bottle causing vigorous agitation. A second length of airline was attached to the shorter length of rigid tubing and to the longer of the two pieces of rigid tubing in the second bottle. Likewise another piece of flexible tubing was connected to the shorter tubing from the top of this bottle and to the longer tubing on the third bottle and so on. In this way a single pump can be used to raise 6 (or more) bottles of brine shrimp nauplii. The hatching rate using this method is high. The fry were fed 2-3 times a day initially and were seen "striking" at the nauplii within a few minutes of their first introduction to the tank. The ingestion of the food was soon obvious by the bright red bellies of the fry. At this stage a small "hang on" filter containing filter floss and carbon was fitted to the tank. The fry grew rapidly and were typically estimated to be approximately 180 in number and appeared to thrive until their 18th day when they all died within 24 hours. The whole process was repeated a dozen or more times, the fry always dying at the same stage of their life. With later batches, attempts were made to feed "Liquefry" and dry food with the brine shrimp nauplii after about 10 days. However these foods did not appear to be taken. Eventually the author had to abandon the experiments due to pressure of work involving extensive travelling. The A. clarkii and the anemone flourished in the tank for a further two years until the whole set up was given away when job requirements necessitated a house move.
Conclusion
A. clarkii fry can be raised to 18 days of age using brine shrimp as the sole food. An anemone believed to be Heteractis magnifica (Radianthus anemone) has been kept for 5 years in a tank fitted only with an under gravel filter. It would appear that regular feeding is important for good health of these creatures. This article was written at the request of Derek Scales and relates to work carried out between 1979 and 1981. I was obliged to give up the hobby in 1984 and am shortly to resume my marine fish keeping. The technique described above was very similar to one which I had previously used to successfully breed and raise many hundreds of freshwater angelfish (Pterophllyum scalare), which I used to sell to local aquarium shops to partly finance my hobby. Returning to marine fish keeping after this long break, I have however been surprised to find that it appears to be taken as fact that clownfish require rotifers as a first food. My experience is otherwise and I wonder if this is just one of those things that passes into "folk lore" without being tested. My suspicions are that many of the other larger clownfish species, and probably also many other marine fish, can be raised using the technique described above. If anyone wishes to try to repeat this work, it may be important to note that the brine shrimp were of the "San Francisco Bay" variety. It is my understanding that the nauplii of these are smaller than those of other varieties. From reading current literature, I realise that my mistake was not to wean the fry onto other foods at an early stage. I understand that commercial breeders wean fry on to dry foods as early as 3 days after hatching. I have also been puzzled by many of the correspondents to the Reefs UK chat group stating that they have problems keeping anemones. The lighting I used was far from what is specified as being desirable these days. I must say that my anemone was always white in colour, probably due to the absence of zooxanthellae, but with regular feeding it thrived, it what must have been very poor water conditions. I suspect that water condition may not be as important as we have thought for these creatures. I have just returned from a holiday in Singapore and while there took a boat trip to an island a few hundred yards in diameter and only about two miles from the Singapore waterfront and docks, and close to a busy shipping lane. At low tide I found an anemone (species unknown) of about 6 inches diameter in apparent good health. On the other side of this small island was a much larger island completely filled by an oil refinery! I appreciate that the article is short on detail in one or two places. I made daily notes at the time and still have these. However after two house moves (the second from England to France) I am unable to find these at present. When building work on my current home is complete, I hope to be able to recover these and maybe add some "flesh" to one or two places in the article.