What Can Cause Berghia Nudibranches to Fail in Your Tank?

Originally posted in 2006

Updated in 2025

Are Berghia the right choice for you in your war on Aiptasia?
Berghia stephanieae Nudibranch, Grasping Their Point Of View

Calcium Spicule Matrix
A Berghia’s Point Of View
This is a picture of the matrix that makes up the tissue inside an encrusting gorgonian. And the obvious question is; What does this have to do with Aiptasia and Berghia? Did you realize that these gorgonians were made up of all these little spicules built from Calcium? The point is that there is a lot more going on in the unseen and microscopic world than we give thought to. Each tank has a predator-prey relationship and creatures fighting for space, competing over leftover food and trying to survive. Some are stationary, some very mobile. Some are very large peanut worms, some are predators, some are huge compared to a Berghia. Extra large brittle stars and monster serpent stars are significant predators, even to fish, species dependent. There could be times when the Berghia are outnumbered by Aiptasia or outmaneuvered by things like peppermint shrimp or large stars like these mentioned and injured to the point that it slows them down after such an encounter.

But more than likely when it seems to take forever to thin the Aiptasia there’s a much simpler reason revolving around the predator-prey relationship between the Berghia nudibranchs and the numbers of Aiptasia anemones that exist but are not seen. Then considering the Peppermint shrimp (Lysmata sp.), they are among the most dangerous shrimp to have in a reef. They eat far more species than given credit for as they get larger in the home reef. Since peppermint shrimp are very shy and nocturnal, reefers will seldom see it happen because Berghia are also nocturnal. This is a safety precaution due to the overall habits of camel and peppermint shrimp.

Anything that will tear a cucumber apart, shred an LPS, pull tunicates out of holes in the live rocks and eat nearly all species of tropical anemones like a mature peppermint shrimp will, must be regarded as a danger in the reef aquarium. Peppermint and camel shrimp have not been confirmed as actual predators on Berghia nudibranchs but their habits include preying on many species in the reef system, including some corals. We generally do not find many forms that prey on nudibranchs because nudibranchs store and concentrate chemicals and stinging cells from their prey and they are nocturnal. Cleaner shrimp, also a Lysmata species, are perfect shrimp for a reef and do not bother the Berghia nudibranch at all. Advanced aquarists with experience keeping Copperbanded Butterflies (Chelmon rostratus) may combine these two natural predators, Berghia and the butterfly, for a great team and positive effect. But, the nudibranch will be effective without any help from fish or chemicals in your reef system.

With both sets of antennae raised in the “V” as if to signal a victory in the war against Aiptasia, these nudibranchs lead the way in the fight. If Berghia are to be successful, we must understand a bit of the ways that Berghia work and what can cause a seeming failure. Berghia always eat Aiptasia – Always. Occasionally reefers will say they don’t work, but that their Aiptasia don’t seem to be as thick as they were. What is it that causes the delay or helps an Aiptasia population win? Can the Aiptasia win?

Licensed in laboratory technology, we’ve spent time studying Berghia biology in our own lab in order to give you the best possible information and advice. Here is a case when you should consider this from the Berghia nudibranch view. Let’s consider a 30 gallon reef. The algorithms from the previous page come out with 2 to 3 Berghia. There are no large predators of any kind, algae is kept under control by several dozen micro blue leg hermit crabs, hundreds of bristle worms and nearly 50 small snails. There is a pair of cleaner shrimp and a pair of adult Percula clowns hosting in a Rose Bubble Tip Anemone (RBTA) and numerous corals. Lights are 1 10K halide and 2 actinic 03 pc’s. The overflow runs into a 20 gallon sump/refugium that is lighted on opposite day/night cycle from the tank.

Conditions are perfect, the tank is very stable but we’ve picked up a couple Aiptasia on frags and Ricordia rocks from friends and dealers. After trying kalk injections, the Aiptasia that were attacked have come back and are larger than ever before and there are a few more. 5 large Aiptasia on one rock at the far end of the tank from the overflow, one huge Aiptasia in the middle and one huge Aiptasia close to the overflow. They survive no matter what we’ve done. So, thinking Berghia will be the answer, considering getting a trio-pak. The algorithms from the previous page say 2 to 3 Berghia will do the trick. Three is the optimal number, there’s really only 8 to 10 large Aiptasia.

There are 3 considerations. First deals with acclimation. You must acclimate them better than most people are ever taught to acclimate and not blow their world all to pieces by just dropping them into the tank. Please see the Acclimation Instructions page for helpful information on this and put some thought into it. Acclimation is so very often underachieved and incompletely done that it is the major cause that initiates ick, popeye and fin rot diseases in most fish and death to inverts. High mortality rates in fish and invertebrates and most disease issues are due to incomplete acclimation. Bad practices will kill reef creatures and even though these Berghia are extremely forgiving of mistakes, they are still no exception!

Normally just filling the bag one time will not equalize the pH and salinity between the animal in the bag and reef water chemistry. This is due to the buffer system in a marine tank that tends to resist any change. Reefers using kalkwasser, calcium boosters, and/or buffers, will have water with dKh values far above the water in the bag. Changing the dKh values in the bag from normal to above normal to match the reef tank too fast will result in death to invertebrates and changing the salinity too fast or not completely enough will cause salinity shock in fish/inverts resulting in damaged mucous membranes. This gives diseases the opportunity to attack and succeed due to the additional stress put on otherwise healthy animals by incomplete and brief acclimation.

Our young Berghia must also be acclimated carefully. It’s not hard, they go easily into higher salinity and dKh so long as it’s gradual. It is simply impossible to make the case strong enough for good, gradual (longer than you do now), complete acclimation practices. After shipping, the pH in the bag is lower, the CO2 is higher and shifts have started to occur in the chemical balance. Gradual and complete acclimation will reverse this slowly. Slow is good in this case. It’s not a race. The more kalk you use, the more you should extend your acclimation time due to the change in dKh.

Next consideration is the rock setup. Will the Berghia be able to get from one place to the next in your reef or is the way completely blocked by a huge RBTA? Is there a natural bridge of rock work or a huge desert of sand bed? If the only way is a huge desert of sand bed, they may simply just refuse to cross it. How would they know there was an Aiptasia on the other side anyway? Water currents would blow the scent away.

Last is the way Berghia attack on a larger Aiptasia. It can require a group of Berghia in a coordinated attack. Large Aiptasia that have been well fed, especially if some other treatment to kill them was unsuccessful, are very stout. They are thicker than normal, tough and normally have a highly concentrated zooxanthellae. They are tough and very nutritious for the Berghia. Let’s say one Berghia starts to eat on one of the 5 Aiptasia where you put the little colony of Berghia. It’s impossible to eat all of that meal, it’s so huge and rich. So, like a small cut, that Aiptasia grows back quickly. It also gets a little stressed out and sends off 30 pedal lacerates in the other direction. These are tender and highly nutritious. The next day the Berghia comes back to the same anemone to realize there is a very tender, highly nutritious meal of basal cell lacerates on the other side. This could go on for a long time before the Aiptasia is worn down.

When 3 Berghia gang up on it for several days, they will take it out. But it’s possible the 3 may not find each other often to make a coordinated attack, so it seems to take a while in some cases. It could take more Berghia. In this case, patience is a good friend. It may not work out until some eggs hatch and are able to mature that this Berghia stephanieae Nudibranch Larva At 3 Days Microscopic Berghia Larva Attacking Aiptasia White egg yolk covered by zooxanthellae after Aiptasia bites will happen. And it does take a balance between the system size and number of Berghia in the original colony. That’s where the algorithms come in as a handy guide. But they are only a guide because of so many variables.

When The Algorithm is Wrong:
Following the formula would call for up to 60 nudibranchs to start a couple colonies in a 600 gallon system, but this can be overkill. But then imagine a 600 gallon reef with only 3 little Berghia. It’s just a simple matter of impossible odds that such a small group of Berghia will achieve results in a system that large. With so many variables and the fact that colonies reach a point when large enough they achieve a positive synergy, 18 may be enough in a 600 gallon tank if placed all in one spot. In this case the algorithm would be way off.

There is also the factor of Aiptasia population and algorithms can come up short even if started out all in one place. It takes some thought, and then a best educated guess. Obviously following the algorithm will conclude that 1 Berghia is good for a 10 gallon tank. If that tank contains 3000 modest sized Aiptasia, then this Berghia will live a good life in that tank and no decrease in Aiptasia will be noticed unless that 1 Berghia (without a mate) lays an egg strand and some larvae survive from this one strand. If you get impatient in the 3 to 6 months this takes to happen and try kalk again, neglect reef husbandry or use a chemical on the Aiptasia, you have tainted their food and probably will result in killing the young Berghia.

In another case, let’s consider a 180 gallon brick loaded with live rock. There is about 100 moderate sized Aiptasia in a few places. Tank size in gallons plus the refugium and sump could easily calculate out to be 18 Berghia nudibranchs or as few as 12. In this case, it would be more efficient to consider the tank like several separate tanks. In other words, divide it into a couple of 50 gallon tanks to figure out the Berghia colony size. If there are only 100 Aiptasia plus their unseen basal cell lacerates and little Aiptasia too small to see, then perhaps a startup colony of 9 Berghia is all that’s needed?

The trick to this working is a balanced combination of patience, square yards of actual live rock outer surface area, the size and mass of the Aiptasia population, both easily seen and unseen. If the reef keeper gets everything right the first time for the Berghia colony size, acclimation, placement of the startup colony and tank mates, the Aiptasia are definitely done. Since Berghia will not alter any water quality, a direct benefit can be gained by adding more Berghia if the original colony proves to be too small for the application.

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In Conclusion:
It’s understandable if you don’t see anything happening and you don’t see the Berghia. They hide a lot of the time. The best time to see them is often in the first couple daylight hours after sunrise (ours, not an artificial one created by lights in the tank) on the hard current side of the rocks. Thinking the Berghia are no longer in there and lacking patience can be large mistakes. Remember, Aiptasia spawn sexually and asexually.

If you don’t see a lot of baby Aiptasia near the larger ones, then the Berghia are doing their job. The Aiptasia can be too isolated to encourage the Berghia colony to migrate. It’s not common, but it does happen. It is also possible some nasty little creature or a turbo snail could hurt a Berghia by accident and slow its progress considerably while migrating. That’s life in the reef and part of the dynamic that makes this hobby so much fun.

If Berghia don’t get all your Aiptasia it’s entirely possible the numbers of Aiptasia in the tank did not justify a Berghia colony or there were simply too many Aiptasia for the number of Berghia you got or your acclimation procedures need some tuning. If you didn’t succeed the first time, add some more to get a more robust size to your Berghia team. Remember, Berghia always eat Aiptasia and Berghia are a tool. Use this tool with reasonable insight and get desired results.

Berghia also make cool pets for nudibranch lovers and are excellent in captivity because they are captive bred, tank raised. We know exactly what to feed them for a great experience and happy life in a specialized tank – Aiptasia!

You can see a picture of a dynamic reef full of many thousands of invertebrates and 10 very active fish where these nudibranchs worked to completely remove thousands of Aiptasia on the Learn About Aiptasia To Kill Them link.

Finally to answer the question; Can Aiptasia win? Let’s just put it this way: If you have Aiptasia that you absolutely love, make very sure that no Berghia verrucicornis (Aeolidiella berghia stephanieae) nudibranchs ever get into the same system with them.

Berghia depend more on chemical receptors than eyesight to target Aiptasia. Their rhinophores are extremely sensitive and have receptors and nerve bundles to target their Aiptasia prey. They also use these sensitive organs to find each other.

Aiptasia seem to be able to sense Berghia. On occasion it appears that an Aiptasia will try to “run” from the Berghia nudibranch and we do have a couple pictures of this event on file at INSTAR. Aiptasia will also move upward toward the top side of the rocks when a Berghia colony is present. Berghia colonies do have a distinct pheromone they use to keep track of each other. This upward migration of a large number of Aiptasia that can follow the addition of Berghia in some reefs has the appearance of an Aiptasia bloom in some tanks.

This means things are starting to work and there is a long road of patience ahead for the reef keeper. The Berghia always catch up with the Aiptasia and then the Aiptasia’s done. There’s no Aiptasia here and when there’s none left in your tank, that’s the point. Reading the documentation on this web site will help each reef keeper accomplish Aiptasia control with Berghia, the healthiest possible way to control Aiptasia in your tank.