The Berghia nudibranch, an outstanding natural way to control the aiptasia anemone
“The enemy of my enemy is my friend” (ancient proverb)
Those words sum up the essence of why the Berghia Nudibranch, Berghia stephanieae, is so popular in the aquarium hobby.
The dreaded and maligned aiptasia anemone is generally considered to be an uninvited and invasive pest. They are supremely adapted to survive in our tanks and reproduce with reckless abandon, stinging our invited guests (the corals) into submission.
There are a few commercially available products to help control the spread of these pests, like Aiptasia X:
Another popular product is called Joe’s Juice:
But the process involves injecting the unsuspecting invertebrates with a lethal chemical injection–one, by one, by one, by one, by one. If your tank reaches plague proportions, you would have to quit your day job, if you wanted to eliminate them from your tank.
Plus, if you’re like most of us, you may be looking for a more natural way to fight this pest in your tank.
(Enter the Berghia nudibranch)
What is a Berghia Nudibranch?
The Berghia Nudibranch is a small invertebrate naturally found in the Atlantic Ocean, Caribbean and Mediterranean seas. It usually reaches about 1″ long, with some individuals growing slightly larger. Their backs are covered with tiny tassels called cerata.
How do you pronounce “Berghia Nudibranch”?
Let’s start with the hard-hitting questions: how do you even pronounce “Berghia Nudibranch”?
What do you call more than one Berghia Nudibranch?
If you have one, you have a Berghia Nudibranch. If you have two or more, you have Nudibranchs
What do they eat?
The Berghia Nudibranch is a specialized predator that only eats Aiptasia anemones. Which is exactly why they are popularly added to our tanks as a natural way to control aiptasia.
The only problem is that they are so specialized at eating aiptasia, they will starve once they clean out your tank.
How many berghia per tank?
The two sites specializing in selling berghia nudibranchs recommend no less than 6 per tank (in any size tank) and otherwise approximately 1 for every 10-12 gallons of aquarium volume. The rationale for this is that if you hope to eliminate aiptasia from your tank, the berghia will need to find each other to gang up on each individual anemone (that’s how they hunt and take down an anemone) and they will need to find each other to mate and reproduce. The original population is likely insufficient to eradicate the anemone pests, but it is when you have established future generations of the sea slug that you will reach a level where elimination can be obtained.
If you don’t order enough berghia, they could starve or get eaten (by shrimp, crabs, wrasses, etc.) before they reach a population size suitable to complete the task.
Behavior and tank mates
Berghia nudibranchs will not harm corals or other invertebrates. They will only eat aiptasia anemones. In fact, they won’t even eat Majano anemones (a close cousin of the aiptasia).
If you have a six-line wrasse or a long-nose hawkfish, you may want to think twice about adding berghia to your tank, since the berghia will be a nice little appetizer for them. Peppermint shrimp, also added to tanks because of their taste for aiptasia flesh, also eat berghia nudibranchs, which seems ironic to me. Especially because you wouldn’t need to add both, if the much more readily available peppermint shrimp just did their job in the first place.
Berghia Nudibranchs will mate and lay eggs once they reach maturity. It is generally recommended to start with the 1/2 inch size, to ensure best chance of establishing a breeding population in your tank. A breeding berghia nudibranch lays eggs once every 1-3 days.
Where to find them
Because Berghia nudibranch’s need a constant supply of aiptasia anemones to survive, they may not be in stock at your local fish store. It’s not to say that your local fish store wouldn’t benefit from them.
After all, how did you get the aiptasia in your tank to begin with? But I suppose seeing a bunch of Berghia swimming around would send a negative message to shoppers.
If your local fish store doesn’t have them, you can pick them up online. Check out
For more information
The Berghia nudibranch is usually purchased specifically to handle the pesky and dreaded aiptasia anemone. If you want to continue to learn more about other common aquarium pests, check out these other articles:
The dreaded bristle worm
How to get rid of green hair algae
Or check out this video to learn more about the berghia nudibranchs