Do clownfish eat their own eggs or babies?
That’s one of the most common questions I hear when it comes to clownfish breeding. Here are 5 reasons clownfish eat their own babies.
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In the ocean, there are two primary methods by which saltwater fish spawn. The two methods are Broadcast spawning and Demersal spawning.
- Broadcast spawners release and fertilize their eggs into the water column. The eggs hatch into larvae that float towards the surface and drift among the plankton until metamorphosis when they settle onto their place on a reef.
- Demersal spawners lay their eggs on a substrate—a rock, the aquarium glass, a location carefully selected by the parents and generally cleaned and tended to by the male.
Clownfish are demersal spawners. The pair lays their eggs on a rock or the glass wall of your aquarium. The male cleans and prepares the site and tends to the eggs, fanning them with his fins and using his mouth to rasp away algae. He watches over the eggs closely.
As a natural and arguably advantageous behavior, the male clownfish tends to the nest of eggs closely, fanning the eggs with his fins and rasping them clean with his mouth, keeping water flowing in between and around the eggs keeping away fungi and predators. They also remove and eat unfertilized, non-viable, and infected eggs.
And while this very natural and advantageous adaptation helps then cull the weak, damaged, and sickly eggs, it does seem that this natural behavior can sometimes go awry and lead to them eating their own eggs in a few predictable scenarios.
Even though clownfish are generally good at raising their own babies from eggs, a few circumstances and environmental stresses may lead the male clownfish to eat their own eggs. It is generally the male since he is the one tending to the nest.
The male clownfish will generally stay very close to the nest of eggs and will tend to them. If he detects any of the eggs as non-viable, he will eat them. The non-viable eggs likely were not fertilized. As fertilized eggs develop, you can see the baby clownfish develop through the transparent outer casing of the egg. But the unfertilized eggs become pasty-white and will be eaten by the clownfish.
If the clownfish did not eat the nonviable eggs, they could attract harmful bacteria and fungus, putting the entire clutch at risk.
One common way that clownfish eggs are lost is from a fungal infection. An attentive male clownfish, tending to his clutch, will eat the sick and infected eggs.
Young and inexperienced pairs often need a few breeding cycles to get it right. While they’re figuring things out, younger couples do sometimes eat their own eggs.
Biologically speaking, it takes a lot of calories to produce and tends to a clutch of eggs. If the parents, probably the male, are starting out from insufficient calorie stores, the temptation of caviar may be too strong to pass up.
The last scenario that might cause your new clownfish to eat their own eggs is if the tank, or the particular place in the tank where they chose to spawn, is in a stressful, high-traffic area. I’m not sure whether the additional stress distracts them during their normal cleaning duties or if excited fight-or-flight responses lead to carelessness and damage to the eggs, or perhaps any other situation. Still, nervous parents may eat their own eggs. One of the best things you can do is give them space and help keep things quiet (in terms of vibrations).
Aside from these special circumstances, however, the fate of the clownfish species pretty much depends on them not eating the next generation. So, as you can imagine, clownfishes are genetically predisposed to raising viable clutches of eggs and not eating them.
A great resource for more information
If you want to learn more about raising your clownfish eggs, I recommend you check out Joyce Wilkerson’s authoritative text on the topic. Pick up your copy of Clownfishes here.
What to read next
Dive deeper into the underwater world of clownfish with these other great articles on the topic: