Tale of an Accidental Clownfish Breeder

The breeding pair of Black Ocellaris Clownfish live amid these splendid Bubble-Tip Anemones (Entacmaea quadricolor), at the right.

by Lars Kläning

Web Extra from CORAL Magazine

“Have fun with it” said the saleslady after I had hefted a 5-gallon (20-L) complete aquarium set-up for freshwater shrimps onto the conveyor at the check-out in a major pet shop.

Naturally she had no idea what I was planning to do with it. And why should she, as although this shop did have a marine section, it didn’t stock any sort of special equipment for breeding marine fishes. No top quality Artemia cysts, no phytoplankton, not even any HUFA-enriching supplements, though I could in fact buy proprietary-brand Artemia cysts there. But I certainly didn’t intend to keep freshwater shrimps.

The male fish watches over the spawn and oxygenates the eggs, tending them with unceasing dedication.

My mission had started when I discovered a clutch of eggs laid by my black Amphiprion ocellaris in my community reef aquarium. And thus I was now back home sitting in the dark in the living-room, waiting motionless in front of the aquarium. All the current was switched off and it was stiller than ever before. I wanted to catch fish fry. My cat observed the nocturnal activity with great curiosity– at last, goings-on at night—and she wanted to play. “No, Hathi, tonight we’re working on a research project!”

It was unusually quiet in the room, no humming of pumps, no bubbling of the protein skimmer to disturb my concentration. I had no idea what to expect, not even what the fry I was stalking actually looked like. Only in theory.

Every half hour I switched on my hand-lamp for a few minutes – a ghostly atmosphere. A small white object broke free of the bottom and moved slowly upwards in the light of the hand lamp. Excitedly I held my breath, only to be rapidly disappointed when I realized it was just a bubble of gas rising to the water’s surface and bursting there. And if my eyes didn’t deceive me completely, the Pajama Cardinalfish (Sphaeramia nematoptera) swimming by in the darkness had a hint of contempt on his face.

I took a break in the kitchen, where the light was on. I’ve been a marine aquarist for a long time and am thus an old hand, and had long thought it must be great fun to raise coral fishes oneself. I’d never made any serious attempt at it, but I did have the book by Wolfgang Mai, in which rearing anemonefishes is described as feasible.

Breeding marine fishes doesn’t always have to be terribly complicated. It can also be small-scale and improvised, as with this rearing tank, just five gallons (20 L) in volume and with minimal equipment.

Back to the aquarium. And lo and behold, the first fry could be seen as points of reflected light. I had never previously seen Amphiprion fry, but I was sure that must be what they were, and so I took the glass beaker and scooped like mad! I wasn’t at all sure how quickly to submerge the beaker, and sometimes the water spilled back out again. I emptied beakerful after beakerful into the little rearing tank, without being able to see how successful I was actually being. By the time I could see no more fry in the light from the lamp, the rearing tank was easily a third full of water. And only then did I allow myself to switch on the room light for a moment. And yes, there really were little fishes swimming in the tank. I was jubilant!

After topping up the water in the main tank, closing the cover, and setting all the equipment going again, I finally went to bed. Next morning I counted approximately 10 live and four dead fish fry. More in hope than expectation I added the first Artemia nauplii. Despite the poor outlook I took photos, as in the final analysis I was proud to have at least seen genuine anemonefish fry. I planned to treat this first attempt as the motivation for subsequent more serious and better prepared attempts at fish breeding.

But it didn’t turn out that way. Against all expectation the fry survived! I did, however, make mistakes. For example I hadn’t installed any heating, and the cool temperature – 71.5 °F (22 °C) – led to the youngsters developing only slowly. Then the nitrite level rose. I didn’t realize this, but described my observations to other aquarists and received valuable tips. Thereafter I performed additional partial water changes using water from my main tank. In addition, I initially neglected to sieve out the older Artemia nauplii, which resulted in an extremely high food density with no nutritional value.

A tiny Amphiprion ocellaris “black” in the hand of the author, shortly after metamorphosis.

Not until a week later did I have the opportunity to buy better-quality Artemia cysts as well as phytoplankton from a well-known hobby dealer in Bremen. (I should have been feeding rotifers and using phytoplankton from the beginning, but apparently there were enough prey items in the water from my well-established reef aquarium to sustain this little hatch of Ocellaris larvae.) By now I was quite determined to rear this first brood. Every advance in the development of my little fishes was reason for a minor celebration! The head stripe appeared, and a short time later the central band. The fins developed color and the behavior of the little fishes altered – my fry were becoming real anemonefishes.

The outcome: five fishes survived! A laughable number for a “real” breeder, but a great success for me! Five little anemonefishes, some with missing stripes and thus not “fault-free” as the professional would term it, but absolutely delightful nonetheless!

I would most warmly recommend every aquarist to try his hand at breeding anemonefishes. Not because there is any likely prospect of commercial success, but simply because it is an important aspect of our hobby and in addition an incredibly thrilling experience. Much more exciting, I find, than watching a coral growing or encouraging every last scrap of color out of it. But I must warn you, it’s addictive! My main aquarium has suffered an element of neglect, as every minute of my spare time has been spent in front of the little rearing tank watching my baby fishes.

A band of young fishes hugging the shelter of the heater-stat – a sight to warm the heart of the onlooker. Every aquarist should experience fish breeding at some time!

Acknowledgements
My heartfelt thanks to Torsten Luther, Peter Schmiedel, Uwe Schmidt, and Thomas Engels, who supported my “Project Fish-breeding” with advice and practical help.

References
Mai, W. 2004. Voraussetzungen und Hilfsmittel zur Nachzucht von Korallenfischen. pp. 108–115 in: Brockmann, D. (ed.): Nachzuchten für das Korallenriff Aquarium. Birgit Schmettkamp Verlag, Bornheim, Germany.
2008. Clownfische im Meerwasseraquarium. Pflege und Nachzucht. Natur und Tier Verlag, Münster, Germany.
Wittenrich, M. 2007. The Complete Illustrated Breeder's Guide to Marine Aquarium Fishes. Microcosm/TFH, Neptune, NJ.