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The Berghia Training Program

By Eric Borneman. Posted to ReefKeepers emailing list, Thursday 25th June 1998.

I have gotten besieged by people requesting information for what I actually did to get my Berghias to survive and thrive. I know Morgan Lidster is currently working on article to describe his experiences with these critters, and I guess I will do my version right here, right now. What I offer is what I did, based largely on Morgan's advice and the lessons learned from my miserable failure with these nudibranchs in earlier trials.

Morgan had promised me some breeding age adults. He sent me six. Two were "breeding" size and age...and were still VERY small . .the others were the nearly microscopic size I had received before from Aquatic Wildlife. I knew from previous experience that these tiny animals were easily "blown away", and I suspected that they were also killed by other animals in the tank...not sure if Aiptaisia ate them, fish nipped at them, decided they tasted bad, and left them mortally wounded, or if they were simply consumed by some predators who just didn't care. Furthermore, these nudibranchs store the nematocysts in their cerata, and they arrive fairly pale...i.e, their defenses are not exactly abounding.

I had already moved my aiptasia filled rock into two thirty gallon tanks in a back room. no predators, save perhaps the unintentional crab or carnivorous polychaete/copepod/etc that one can never be all too sure of not having present. And, you have to understand, I am not talking about a few dozen or a few hundred Aiptasia. I am talking about thousands upon thousands, from lacerates to big huge ones...this has been a battle of mine since I started the hobby and I have almost had nervous breakdowns from them. I shut off the pumps, let the nudibranchs crawl onto my finger tip, and then let them crawl off my finger onto a rock in the tank, not near any aiptasia. They all walked off happily, and I never saw them again for three weeks.

I was frustrated, told Morgan, and he sent me two more adults (relative adults .. they were still TINY). This time, I did as he suggested. I set up a two gallon tank, with only an air bubbler (no stone, just rigid airline), and a fine layer of sand with a bunch or tiny Aiptasia in it...most were less than 1/4" tall. I watched them each night, and they would slowly walk to an anemone, tap at the base with their antenna until the anemone withdrew, and then consumed it...process took a few minutes per aiptasia...when they encountered an anemone even slightly bigger, they would tap it, get stung, and run away. wow. I was not hopeful!

Still, forty eight hours after I added these guys, they laid a spiral egg mass, and continued to do so every other night for a week and a half. And they grew. I suggest anyone get a copy of the article from the Breeder's Registry and/or the journal articles referenced in it for more information here. I knew the eggs would hatch in about 10-12 days, with the larvae drifting(often getting stuck to the water surface) before settling...once they settled and started crawling, I needed to have lots of baby aiptasia ready as they would start eating a day or two later. The first egg mass hatched in 14 days, the others correspondingly later .. a few never fully hatched out. Oddly, I never saw any of the tiny nudibranchs, and still haven't to this day. I did notice a proliferation of those tiny clear brittle stars on the glass after each hatching, and I suspect they may have been feasting on the larvae or the babies? I do not know for sure. Even with a magnifying lens, I could never see any "action"

Anyway, approximately a week after introducing the pair to the two gallon, I again peered into the thirty gallon just in case I could see a survivor of the original six. Lo and behold, I counted eight on the glass! First time I had seen them, and there were more than I had originally added...mostly, they were small ones...about the size of the original "adults". I also knew that the "adults" in the two gallon had grown a LOT in the week they had been there, and were already significantly larger than these eight on the glass. I had to surmise that these were all some offspring of the originals! Cool!

A few nights later, I noticed that I now had three Berghia in the two gallon where once there were two...and while the original adults were already quite large, one was larger, and the third was smaller...and NONE of the eggs had hatched at this time...asexual fission? I have no explanation other than that?

In any event, the three (formerly two) adults continued to consume all the aiptasia in the sand and on the glass, and so I added some small pieces of live rock with aiptasia. At that point, the nudi's were no longer observable day round. They crawl into the rock, and attack aiptasia largely from behind and underneath, if possible. I am quite sure they also began laying egg masses within the holes in the rock. I never saw any more egg masses on the glass but now, several months later, I have seen eight adult nudibranchs in that tank, knowing there are more .. the two original adults are both well over an inch long, and they are grossly different in appearance...they are much larger, more opaque, less "frilly", and they munch down small aiptasia within seconds, and tackle larger ones, as well. I have now disbanded the two gallon, and have added the lot of them to the "other" thirty gallon tank to begin their work.

In terms of the six (then eight) in the original thirty gallon tank, aiptasia populations began dropping rapidly. A few weeks after sighting the eight, I counted twenty four. Some nights I rarely see one, other nights I see upwards of thirty. Every night, however, dozens of aiptasia are gone. Amphipods like to join in the feast as the aiptasia die, too. Usually three to five Berghia attack from every angle on larger aiptasia, all sucking up the tissue from the base up. Amphipods will dash across their backs and grab a chunk of aiptaisia and mucus, very aggressively. The Berghia "packs" take about ten minutes to consume a large aiptasia. They continue all night long (they start appearing an hour or two after lights out), and then vanish during the day. Over the past month, I have had to add about five pounds of live rock every three days, since the Berghia have completely wiped out the Aiptasia in the thirty gallon tank. I have also started to move some of them, as I can catch them off the glass, into other tanks, even a few into ones with fish. It is too early to tell if they are going to survive, as five or six Berghia in a larger live rock filled tank are hit and miss as to whether you will actually be in the right place at the right time to see them. They are there, though.

I set up a tank to house James Wisemans corals and fish while he moves to Houston. I had a few pieces of live rock in that tank, and over the past few nights, I have moved sixteen adult Berghia off the glass from ones which were living in that rock. And this is rock that was long cleared of Aiptasia, too! They are getting quite pale .. last nights "crop" must have been quite hungry. I really have no idea how many I have, but I do know that Aiptasia populations are declining rapidly and Berghia are climbing. I would surmise I have seventy or more...could be much more, I doubt it is less.

Now..two caveats...first, don't expect miracles. I have watched adult Aiptasia spit of several dozen pedal lacerates in a couple of days...the Berghia eat all the little ones first, then go after the parents (who continue to lacerate until they are eaten). I have been at this for three or four months and have really only cleared out about sixty pounds of live rock...yeah, that's pretty good, but the rock is TOTALLY devoid of aiptaisa...I am not seeing new little ones I "missed" reappearing. And the Berghias never get full! LOL.

Second, there is a dilemma I have yet to resolve. Since these guys dwell in the rock, what do you do? If you let them clean off rock totally, they will die. If you move clean live rock (with Berghias in there somewhere) to "aiptasia tanks", do you want to take the risk that the clean rock will get repopulated? Its heartbreaking to think of, as the sight of "no-aiptasia-live rock" is a joyous thing! I want to move it to a perfectly aiptasia free area until all the rocks are clean...but what of the Berghias on that rock? You can't get to them, except by moving them off the glass if they show up there? Do you sacrifice them? what a waste! Or do you move aiptasia live rock in with the clean rock/Berghia tank? If you do (as I have been doing), some Aiptaisia will let loose or get on the "clean rock"...and what if the Berghias miss those, since they hang out on the rock where there are large populations of Aiptasia? And, at least in my case, I cannot physically fit all my live rock into those couple tanks...even if I could, what do you do about providing rock for your tanks with fish and shrimp and stuff in there if you move it into the "Berghia clearing" tanks? Do you replace it with the "cleaned off" rock? If you do, what will happen with the Berghia on those rocks? They will starve. Also, will the fish and shrimp really eat them when they get to be the size they are now, fully grown with lots of stored nematocysts? Since they are nocturnal, I am still seeing Berghias in the tank I set up for James with tangs and cardinalfish in there...would they last if there were aiptasia present? I don't know yet. But I'll tell you, I have had worse problems that to keep enough aiptasia around is not something I have previously spent much time pondering...LOL

Anyway, it can be done, folks...and it works, and it is very cool. Like Ron Shimek said to me in an email, though, we have population ecology questions...they are inverse predator prey relationships...i.e, aiptasia goes down, Berghia goes up, and then Berghias starve...a few aiptasia that got missed is all you need to repopulate a tank...and thus far, I have been avoiding this by keeping densities high so that the aiptasia are gone gone gone with so many Berghias...what happens in a big tank with a couple of Berghia only? I suspect that this will not have positive results...I suspect there is every chance that a couple of Berghia in a large tank will never find the few straggling Aiptasia, much as Ron found out. So, they do work, but there are some logistical things that will need to be addressed, unless, of course, you can raise a couple hundred Berghia separately and then let them all loose in a tank...odds would be in your favour then. Or, if you can do as I have done successfully so far, and keep them locally high.

Oh yeah, FWIW, Morgan says (and the journals confirm) that raising Berghia in an unaerated container causes the eggs, once hatched, to largely bypass the pelagic stage, and they go straight to the crawling/eating stage. I did not do this, nor can I say if it would work better or worse...maybe he can address that better.

So, there you have it .. the secret of my far.

Created by liquid
Last modified 2006-11-24 18:40