Clownfish Breeding Journal
The Common Clownfish, Amphiprion ocellaris, is probably the most popular saltwater aquarium fish in the world. Clownfish breeding and raising the larvae from clownfish eggs laid on the glass inside of my saltwater aquarium is one of the coolest things I have experienced in this hobby.
When I experienced this for the first time, I posted observations periodically on this blog. While the information was captured in raw fashion as it happened, the posts need a little tidying up and organizing. Two years have gone by since those first days, and I’ve learned a lot. This post is intended to be a comprehensive collection of the information spread out across those earlier blog posts and from my clownfish breeding journal. And when I say comprehensive…I mean…wordy. Big time disclaimer here–if you don’t want to slug through a seriously long post…bookmark it (or bail) and come back later.
I hope you find the new format here easier to read–and my two hopes for this post are: 1) you learn something about clownfish breeding and the clownfish eggs development and 2) that if you can help add to the content here, you leave a post and help us all out.
On the side is a picture of the female clownfish after laying her eggs on the aquarium glass. You can see the peach-colored eggs on the aquarium glass below her tail. I know she’s a bit blurry in the picture, but what I thought was cool about this photo is that you can see her ovipositor–the tube through which the eggs pass as she lays them.
Clownfish Breeding Journal–Overview
The first time I observed the clownfish breeding in my tank, the pair spawned in the front-right corner of the tank, laying their eggs directly on the aquarium glass. Clownfish won’t always spawn on the aquarium glass–they might choose a rock, tile, clay pot or aquarium decoration.
My attempts and coaxing them to use a substrate of my choice failed many times. I tried tiles, glass and clay flower pots–directly on the aquarium glass or on the clay pot are the only places my clownfish have ever spawned. The picture above shows the clownfish breeding in the front-left side of the aquarium–which is where they relocated after I added alternate spawning substrates to their preferred corner.
The reason you should try to encourage your clownfish to spawn on a removable substrate is because it is much easier to hatch the eggs in the grow-out tub than it is to catch the larvae after hatching and move them to the grow-out tub.
The picture below shows the eggs on Day 2. Not the color of the eggs on Day 2 is still a very similar pale peach/orange color to the day they were laid.
Keeping the Clownfish Eggs Clean: Clownfish Breeding Journal-Day 2
Clownfish breeding Day 2–The male here is tending to the eggs, which is where he spent the majority of his time over the entire 8-day period. The pecking activity seemed somewhat excited or nervous at times–especially if I approached the aquarium too closely. At first, it looked like he was trying to eat the eggs. I knew that this was a normal behavior and that he was just tending to the eggs, but I could not help but wonder if he would acquire a taste for caviar each time.
When he was not biting at the eggs, he seemed to just hover in front of them, beating his pectoral fins, or swimming up and away with a swoop of his tail, only to return again a moment later. After the eggs were laid, he spent the vast majority of his time pecking at the eggs with his mouth or fanning them with his pectoral fins. The female, by comparison was less attached to the nest. She seemed to circle the spawning area, but at a further distance away from the nest, occasionally swimming in closer to interact with the male clownfish. I was surprised to note, however, that despite his apparent attachment to the nest (dare I say…obsession? let’s face it, if those eggs had a Facebook page, he’d be creeping all over it…but I digress)the male clownfish would abandon the eggs all together at feeding time, eat his fill and return to the nest once feeding time was over.
Clownfish Breeding Journal-Day 3
By Day 3, the clownfish eggs changed color from the fleshy peach/orange color to a drab gray. Unfortunately, the number of eggs was dwindling. Anecdotally, I’ve observed this in every clownfish breeding attempt over the past 2 years. The amount of thinning out seems to vary from egg clutch to egg clutch.
Clownfish Breeding Journal-Day 4
On day 4, the number of clownfish eggs diminished slightly, and I found the male constantly guarding and cleaning the eggs. The clownfish eggs continued to change in color, going from a dull gray in day 3 to a shiny/metallic gray in day 4, as the larvae inside of the egg continued to grow and develop.
Clownfish Breeding Journal-Day 5
The most interesting change in the clownfish eggs began on Day 5, when about 5% of the eggs (approximately 1 in 20) developed tiny eyes that reflected the light as the eggs swayed in the water current. Nothing is cooler than seeing those tiny eyes through the egg casing. Seeing the eyes was a reality check that things were progressing much better than before–and that I needed to get prepared. On Day 5 I began to set up my equipment for growing-out the larval fish:
- A black round tub
- Air pump
- Airline tubing with valve for regulating air flow
- Rotifer culture bubbling away
Clownfish Breeding Journal-Days 6-7
Days 6-7–By Day 6, about 3 in 10 eggs had shiny, reflective eyes. By Day 7, the majority had reflective eyes. The eggs seemed bigger somehow (or at least distinct) and visibly swayed back and forth in the current and in response to the male clownfish fanning the eggs with his pectoral fins.
Clownfish Breeding Journal-Day 8
Day 8–The eggs were set to hatch. They were large, reflective silver in color and swayed in the breeze. Eyes were clearly visible in every egg.
I could just imagine them ready to burst–that night–they did. Disclaimer: now, after seeing lots of clownfish breeding attempts from two separate pairs of Amphiprion ocellaris, the day of hatching can vary between 8 and 10 days after being laid. The best advice I can give is to be prepared early with your grow-out tub and food cultures–and check on them starting at day 8.
Clownfish Breeding Journal–Egg Hatching
After eight days of waiting, a lot of nail-biting, and pacing like an expectant parent, the clownfish eggs finally hatched, but not the traditional way. Then–in the blink of an eye–I panicked and made a bone-headed move.
I had intended to use a flashlight to attract the larvae and scoop them out with a bowl, which is the way Martin Moe suggested in his article on breeding the neon goby. My back-up plan was to set up a DIY larval snagger I had made (if they hatched too late into the evening), but I became really nervous because the other fish in my tank seemed to hover around the nest in what I swear was anticipation. I wonder if I was projecting that intuition onto the fish or if they really knew something was up. Either way, what I saw was enough to spook me into changing my plan.
I read a few forum posts about hobbyists actually siphoning eggs out of the tank before they hatched to eliminate the risk of predation, but I’m pretty sure I caused more damage than good by attempting this approach. In the end, only 5 larvae survived the extraction. It almost hurts me to even relive this and type those words. Ugh. Later on, I did attempt to use a DIY Larval Snagger–with mixed results. The Snagger worked ok. The issue was that the other fish in the tank ate more than their share of larvae while they were on their way to being snagged. I tweaked my Larval Snagger and wrote a post about how to make your own DIY Larval Snagger. For what it is worth, I have had better success using the Larval Snagger in tanks dedicated to a breeding pair than in a community display tank, where other hungry mouths perform their own version of larval snagging.
Clownfish Breeding Journal–Problems, Problems, Problems
It would be disingenuous to suggest that my clownfish breeding experiences were all easy from there. Success was difficult at first. A lot of clownfish larvae died. The challenges with spawning and capturing larvae were just the beginning. Rotifer and phytoplankton cultures crashed, essentially starving some of the poor larvae. A cheap heater malfunctioned and cooked a batch of larvae, and undoubtedly, countless poor larvae were damaged by clumsy (unintentionally clumsy) capture and transfer. It is only after having made nearly every bone-headed move possible that I eventually had some success.
The good news is that your clownfish will hopefully breed about every two weeks–providing you with plenty of opportunity to get things right–and the larvae that survive will have been ok with the special kind of rearing that only you could provide. Feel free to post a comment here with any challenges you may be facing. You’re not alone in this. Someone out there has likely had the same issue.
I will get into the food cultures (copepods, rotifers and phytoplankton) in the next section, but for now–just know that they are a very likely spot where you will have some problems. Expect crashes. The best thing you can do to hedge against crashes is to have multiple independent cultures going and save small samples of your cultures, replacing as you progress every couple of days–because you never know when you are going to need it to feed some hungry larvae or to restart a crashed culture.
Clownfish Breeding Journal–Feeding the Larvae
When the larvae hatch, the baby clownfish look like tiny shards of glass with big eyes. They are mostly colorless and the light from a flashlight bounces off the eyes with a metallic sheen. The MOFIB thread on breeding clownfish states that the larvae are 3 mm at hatching. I didn’t measure them but can agree that it sees about right. It’s really pretty small when you see it in action. The really amazing part is how small the mouth of something is when the total length of the entire larva is only 3 mm long.
Because they are so small, if you want to be successful with clownfish breeding, or with breeding any other saltwater fish for that matter, you will need to become proficient growing out (culturing) live copepods, rotifers and phytoplankton.
The basic process of caring for the nutritional needs of the clownfish is to create a culture of phytoplankton, a culture of rotifers, and a culture of copepods if you can find them. In essence, you need to create a miniature food web. You grow the phytoplankton to feed to the rotifers and/or copepods. You grow the rotifers and copepods to feed the clownfish larvae.
I fed the clownfish rotifers until day 10, when I started introducing baby brine shrimp (just hatched). Rotifers are the right size for larval clowns to eat, but they do not have much nutritional value. What little value they have comes from the phytoplankton in their gut when they are eaten. Brine shrimp, by comparison, are a dense food–so you need to feed the clownfish much less. It is also important, when first introducing brine shrimp, to add very small quantities of baby brine shrimp less than 12 hours old. Brine shrimp molt and grow after 12 hours and can reach a size that will actually choke your clownfish, according to Wilkerson’s book. Please note, this is an affiliate link to Amazon.com. The book is not even currently in print–but if you wish to view it on Amazon (to see if you can score it at a local fish store), be my guest. Please note that in the event you buy anything from Amazon as a result of clicking this link, I will receive a small commission on your purchase. No pressure at all.
After several days of feeding both rotifers and baby brine shrimp, I stopped feeding rotifers all together. Similarly, once the fish were eating only baby brine shrimp, I started feeding crushed flake and crushed freeze-dried foods. By around day 20, I’m pretty sure all fish were eating the dry food as well as live brine shrimp. I wrote a brief post on this topic as well, and connected it with a YouTube video of of the young clownfish eating some live brine shrimp.
Clownfish Breeding Journal–Success Raising Larvae
My first success raising larvae happened several weeks later. The fish in my display tank had become quite adept at snagging the larvae before I could and made meals of them. The success came on a night I wasn’t expecting. I must have missed the first day the eggs were laid, because the eggs all hatched one night earlier than I had planned for. My Banggai Cardinalfish were greedily gulping up larvae. I managed to rescue 10 larvae that night. I had rescued larvae before, but this time, unlike the previous times, there was no disaster. No phytoplankton or rotifer crashes, no malfunctioning heaters, no dim-witted decisions were made. I wrote a blog post and posted an unimpressive 9 second video of the Clownfish Larvae Three Days After Hatching swimming in their grow-out bucket. They don’t look like anything more than tiny slivers swimming through some greenwater–but it was progress.
Along with the good fortune of avoiding disasters, I also made a few small changes to my setup. Previously, I was using a 20 gallon black round tub. I bought it at a hardware store–it’s the kind with the rope handles you might purchase for yard work or to hold some sodas for a cookout. But that proved to be too large of a volume to be practical. It is important to keep the density of rotifers high in the beginning. The clownfish larvae shouldn’t have to swim very far to find a tasty treat–and keeping the 20 gallon tub full of rotifers was a challenge. Instead, I found a jet black 5 gallon bucket–and scaling back my operation really seemed to help.
Growth was slow for this batch. At the end of that ordeal, I had one tiny juvenile clownfish survivor. But hey…it was a start…
The clownfish kept breeding, and I had other opportunities to improve my skills. Keep at it, learn from the mistakes you make along the way and eventually you will be staring at a black round tub full of clownfish babies.
For me, it felt like a painfully long time to get to the first success (that little guy above) but after I broke through there, I seemed to have more and more success. In the video below, you can see how different the growth rates were of the juvenile clownfish from one particular batch. Some of the clownfish babies are still dark with only one stripe. Others have two stripes, while a few have gone almost completely orange in color and have grown in to their third stripe. This is related to how quickly they grow. I noticed that the slower growing clownfish also tended to be the ones who were slowest to adjust to the food changes, or were least adept at eating the new foods.
Clownfish Breeding Journal: Timing–How Often Did The Clownfish Pair Spawn?
With two pairs of clownfish breeding on overlapping schedules, I was able to get an overall feel for the general timing of the spawning attempts and how long it takes for the eggs to hatch. Both pairs, in separate systems, turned out to be quite regular with their spawns. In the couple of years I have observed the clownfish breeding, they have gone through periods of extreme regularity and other periods where no breeding activity seems to occur at all.
When spawning regularly, the clownfish spawned about every 10-14 days. The eggs hatched between 8 and 10 days after being laid. Many times the larvae hatched on back-to-back evenings, which will drive you nuts if you are trying to collect them from the breeding tank.
It really is much easier to take care of the fish and rescue the babies if you set up a dedicated breeding tank. The clownfish seem less anxious and they generally leave the newly hatched larvae alone if you need to snag the larvae out of the breeding tank after hatching.
Where to go for more information:
The GO-TO place for you to learn more about breeding clownfish and have a discussion with like-minded aquarists who also share your passion for breeding clownfish is the Marine Ornamental Fish & Invertebrate Breeders Forum.
If you are interested in purchasing a book on the subject, the best book is written by Joyce Wilkerson titled: Clownfishes: A Guide to their Captive Care, Breeding & Natural History. The problem is that this book isn’t in circulation anymore–but if you see it around in a local fish store or from someone getting out of the hobby, snatch it up. It is an easy read, has great pictures in it and is a blast.
The best overall book about breeding saltwater fish is Matthew L. Wittenrich’s book, The Complete Illustrated Breeder’s Guide to Marine Aquarium Fishes. Disclaimer here–this is an affiliate link through Amazon–and I’ll get a small commission if you buy from Amazon. No pressure at all–but I like the Amazon links because you can read reviews and even browse the book online. If you decide it sounds interesting, get your copy from your fish store or book store of choice–just know that if you buy anything via that link–Amazon will know you came from here and the blog gets a small credit. For what it’s worth, Witt’s book is my favorite aquarium book, period. The only reason I put it second to Joyce’s book on the list here is because Breeder’s Guide covers much more than just clownfish breeding. The book covers everything you need to know to get your hands wet and try clownfish breeding. If you’re a nerd like me, you’ll end up sleeping with this book under your pillow.
A third option is Frank H. Hoff’s book, Conditioning, Spawning, and Rearing of Fish, with an Emphasis on Marine Clownfish. It’s not really a fair assessment, because I read the above two books first (and was biased by them) but I found Hoff’s book to be less of a page turner. I read Wilkerson and Wittenrich’s books cover-to-cover multiple times, whereas I found myself skimming through Hoff’s book. Also trivial, but the edition I have of Hoff’s book is not bound as nicely as the other books. The pages are filled with graphs and tables–so it reads more like a research paper than a mass-market book–so if that’s your thing, go for it. This book is also harder to get than some other books. That link was also an affiliate link.
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