Palythoa killed my beaugregory damsel

[adwoodworth]

First, a little background on my tank. I have a 35-gallon hex that has recently been set up as a Bermuda biotope tank. I live in Bermuda, and the reef keeping hobby is off-limits because the importation of anything that will survive in salt water is strictly prohibited and almost all local corals are protected. That means that if I want to do a saltwater tank, I have to limit my inhabitants to things that I collect myself (well, with my kids) from local waters and they must not be on the protected species list.

The tank has dried rock (curing in the sun for, oh close to 160 years) and live sand and I have (or had) a pair of juvenile beaugregory damsels and a pair of sergeant major damsels living happily in the tank while it cycled. On the weekend, I collected two clusters of zooanthids and placed them in the tank. I suspect they are palythoa mammillosa (a.k.a moon polyps, sea mat, button polyps) and zoanthus socialus, (a.k.a green carpet, green sea mat) but I really have no idea and that was the best I could do with the information I had to work with. The zoanthus socialus is wound pretty tight and hasn't opened up yet, still annoyed by the move. The palythoa mammillosa (I think) is much more relaxed and has opened up.

Palythoa Mammillosa and Zoanthus Socialus

• adwoodworth
• Nov 20, 2018

Last night, while observing my fish, I watched the larger beaugregory damsel take a run at the smaller beaugregory damsel (they are still jockeying for position and dominance). While the smaller one was darting from the larger one, he came into contact with the polyp shown in the photo at the bottom of this group, which I assume is a palythoa mammillosa. He went into shock immediately, appearing paralyzed. A few seconds later he began moving again and limped off to hide in a hidey-hole where the larger fellow couldn't bother him. I gathered him up and put him in segregation in the tank, but he was dead within a few minutes.

Being my first go at a saltwater tank, I am wondering if zoanthids/palythoas killing fish by stinging is a common concern, if they usually just learn to avoid each other, or is this polyp in the bottom of the photo something I should remove from the tank while there are only one or two polys? Does anyone have a better ID?

 

[James M]

They look like zoas but it is highly unlikely that they killed the damsel.

 

[adwoodworth]

They look like zoas but it is highly unlikely that they killed the damsel.

I am absolutely certain they killed the damsel because I just happened to be watching him at the moment it happened. He was active and excited to see me (feeding response) and then he went broad-side against that bottom polyp and immediately froze in place, seeming to "stick" to the polyp briefly, then went stiff to the bottom, just like an electric shock.

 

[Foothill Corals]

Welcome to R2R

It may appear that is what happened to you but.... I bet it was aggression from the larger Damels that actually killed it.

 

[James M]

I am absolutely certain they killed the damsel because I just happened to be watching him at the moment it happened. He was active and excited to see me (feeding response) and then he went broad-side against that bottom polyp and immediately froze in place, seeming to "stick" to the polyp briefly, then went stiff to the bottom, just like an electric shock.

They won’t die instantly if they get stung.

 

[adwoodworth]

They won’t die instantly if they get stung.

It wasn't instant, but he seemed frozen for a minute then went off to sulk. I put him in isolation in a breeder net and within a few minutes he was dead. Immediately before contact with the polyp, he was happy and eating.

 

[James M]

Welcome to reef2reef
It wasn’t the zoas that killed the damsel. If that were the case then my blenny that touches the zoas would be dead. Any signs of flashing ?

 

[adwoodworth]

Welcome to reef2reef
It wasn’t the zoas that killed the damsel. If that were the case then my blenny that touches the zoas would be dead. Any signs of flashing ?

No signs of flashing and it was a very sudden change.

 

[adwoodworth]

Better photo of the suspect.

 

[DSC reef]

Welcome to R2R @adwoodworth.
While anything is possible I'm highly doubtful the palythoa had anything to do with the death of your fish and could be coincidental. I don't think palys have nematocysts to actually sting a fish but I could be wrong. All our chromis, damsels and clownfish would actually try to get hosted by our colonies of zoas and palys. Sorry for your loss. Maybe their is someone here that might have had a similar experience.
#WelcometoR2R

 

[saltyhog]

Agree with DSC. Palys don't sting things. Not sure what happened to your damsel but I don't think the paly had anything to do with it. I had a large colony of those palys for a couple of years and fish came in contact with them every day with no ill effects.

It has to be awesome to live in Bermuda and collect your own fish and corals, even if you are severely limited in what you can collect!

 

[Gareth elliott]

Also concur with the statements above. Zoanthids and palythoas have nematocysts but unlike most cnidarians that is not where its deadly toxin is. Instead palytoxin in its mucous. Most likely evolved as a form of protection from predation.

All conjecture but there is the possibility the fish hit the rock supporting the zoas with enough force to injure its spine. Would explain the stun and quick passing.

 

[reef lover]

Welcome to r2r!! Sorry for your loss.

 

[adwoodworth]

Also concur with the statements above. Zoanthids and palythoas have nematocysts but unlike most cnidarians that is not where its deadly toxin is. Instead palytoxin in its mucous. Most likely evolved as a form of protection from predation.

All conjecture but there is the possibility the fish hit the rock supporting the zoas with enough force to injure its spine. Would explain the stun and quick passing.

There wasn't anything particularly violent in the interaction or in the transition from happily feeding. The larger damsel made a move toward him and he ran for cover, as he has for months now in my smaller tank. That put him in proximity of the paly, but at that point the "chase" was over and he was moving in a relaxed manner. When he brushed it he instantly went rigid for a second and was clearly stunned afterward.

Obviously, being cnidarians, the palys have nematocysts and, from this interaction, this one seems potent enough to take down a small damsel (maybe 1" total length).

 

[James M]

We keep telling you the zoas didn’t kill the damsel but you insist they did

 

[PDR]

Welcome to R2R!

To answer your main question, no this is not common at all. I have never heard of this happening. Based on my experience and research I would say it was either a coincidence, or possibly something else that possibly hitchhiked in with the palys.

To be fair, none of us saw it happen so if you are convinced it was the paly, I would just remove it to be safe.

 

[NY_Caveman]

I have had some unsolved deaths in my tank lately. Two fish that died were eating fine the day prior and normal, the next day they were dead. No marks from disease or predation. I had another fish die as well who did show signs of a parasite. I also lost a couple of shrimp. One of my speculations was Palythoa toxin. I have no proof of this, but two things concerned me.

1. I have a BTA who is killing some hitchhiker Palythoa mutuki (?). I assume they are releasing toxins. No deaths occurred until the anemone was added.

2. All animals who died were found in this part of the tank.

Now I find this as unlikely as everyone else does, but I must say, I really have no idea how likely this is. Not trying to stir the pot, just curious if anyone can say for sure if it is possible or not.

 

[oceanrider]

Guys. While I concur that normally palyzoa do not attack nor kill instantly, As a marine biologist I have seen things never documented before occur.

I suspect everyone of us has seen behavior or interactions between diff livestock thst is rare


I had a yellow jawdish that was healthy but I did not want in my display tank , and an injured foxface . I placed both into a 5 gallon quarantine tank. Both fish were breathing hard. Inside the tank there was just one large rock with a colony of about 209 green implosion palyzoas. I actually wanted the palyzoa to open and heal up as few polyps were squished by my bare hands when I placed them in my display tank. I could tell other corals and fish were not happy with this. So I quickly moved the palyzoa into QT tank. Changed water and placed carbon and display tank for better Both my wife and I started runny nose so I opened the windows.
Yellow jawfish was fine for a few days. And even ate. Foxface has injured his mouth crashing into rocks while I caught him and also had destroyers half of his pectoral fins and had a long 2 inch laceration on his body. So I am nursing all 3. But then jawfish went on top of Palyzoa. Then went back under the rock. In 12 hours he was dead. But the fox face did well. Healed up completely in one month

I surmise it was a combination of shock ( fishes can get too excited or too scared and die from the stress). And the palyzoa poison. And the sting from the palyzoa nematocysts

For your case. I would guess that it was the same combination of palyzoa poison. Bullying stress and nematocysts shock. That killed your damsel. Kinda like a dehydrated runnner after a marathon going Into heart attack. Happens frequently at races to healthy men and women.

That is what my diagnosis would be

 

[DMan]

Whenever I see stories like this, there is usually one line that jumps out. In this case it is "I have (or had) a pair of juvenile beaugregory damsels and a pair of sergeant major damsels living happily in the tank while it cycled." First off why are you cycling a tank with fish in it, but that is another issue. And second does not anyone think it may have been because the tank hasnt been cycled properly.
Maybe it was stung by the Paly, But I say the fish died because of multiple reasons. First, an un cycled tank, second adding 4 fish to a new 35g tank is just to many. And third the fish was placed into a breeding net which only stressed the fish to death, literally.
I may be totaly wrong, and I bow to anyone with more experience. But people always seem to look at these stories with tunnel vision. Skipping over what is written right in front of them.

 

[Captain Quint]

Guys. While I concur that normally palyzoa do not attack nor kill instantly, As a marine biologist I have seen things never documented before occur.

I suspect everyone of us has seen behavior or interactions between diff livestock thst is rare


I had a yellow jawdish that was healthy but I did not want in my display tank , and an injured foxface . I placed both into a 5 gallon quarantine tank. Both fish were breathing hard. Inside the tank there was just one large rock with a colony of about 209 green implosion palyzoas. I actually wanted the palyzoa to open and heal up as few polyps were squished by my bare hands when I placed them in my display tank. I could tell other corals and fish were not happy with this. So I quickly moved the palyzoa into QT tank. Changed water and placed carbon and display tank for better Both my wife and I started runny nose so I opened the windows.
Yellow jawfish was fine for a few days. And even ate. Foxface has injured his mouth crashing into rocks while I caught him and also had destroyers half of his pectoral fins and had a long 2 inch laceration on his body. So I am nursing all 3. But then jawfish went on top of Palyzoa. Then went back under the rock. In 12 hours he was dead. But the fox face did well. Healed up completely in one month

I surmise it was a combination of shock ( fishes can get too excited or too scared and die from the stress). And the palyzoa poison. And the sting from the palyzoa nematocysts

For your case. I would guess that it was the same combination of palyzoa poison. Bullying stress and nematocysts shock. That killed your damsel. Kinda like a dehydrated runnner after a marathon going Into heart attack. Happens frequently at races to healthy men and women.

That is what my diagnosis would be

I as well understand what you are writing. I hold a Ph.D. in Marine Biology. I've not researched this particular matter but I concur with what you have written.