Weird Bubble Growth on Opae’ula Shell

Updated 1/23/16, 1/29/16

Some of my opae'ula have developed these weird bubbles on their shell. I began noticing it about a month ago. I have no idea what it is. It looks like some kind of growth or disease. None have died as far as I can tell, and those affected seem to be moving about okay. I looked for clues online but came up empty. I remember my tropical fish developing something similar, and it was usually fatal.

Some of my opae’ula have developed these weird bubble growths on their shell. I began noticing it about a month ago. I have no idea what it is. It looks like some kind of growth or disease. None have died as far as I can tell, and those affected seem to be moving about okay. I looked for clues online but came up empty. I remember my tropical fish developing something similar, and it was usually fatal. I’m posting this photo in the  hopes that someone can provide some answers about what it is and how it should be treated. I’m thinking of doing a water change of 20-50% as a possible treatment. I’m not aware of any medications and hesitate to use any. Another option is to separate the infected from the others, but that would be a monumental task requiring dismantling the coral condominium. But it seems inevitable. Any thoughts?

1/23/16: Yesterday, I did a 50% water change. The tank size is 10-gallon, but 50% is approximately 4 gallons. I mix Instant Ocean Sea Salt with bottled water, 1/4 cup to a gallon, in a plastic gallon container and pour it in over the coral condo to avoid cratering the gravel substrate. The amount of debris that this process flushed out of the condo was amazing. It mushroomed out like gray dust clouds into the open area of the tank. By the time I poured the fourth and last gallon into the tank, the debris cloud was nearly nonexistent. In hindsight, I realize that I should have flushed the condo while I was removing water from the tank by scooping water from the tank and pouring it back in over the condo. This way I could have removed some of the debris too. One problem with scooping water out of a murky tank is the possibility of accidentally removing opae along with the dirty water. However, the debris is more like fine grains rather than powder, and the water clears quite quickly, so I should be able to see if any are in the scooper. If not, then I’ll just do it as I normally do. Up until now, I had assumed that water changes weren’t necessary. However, with the disease and the debris, I’ll probably do a water change 2-3 times a year. More or less, depending on results. I’m hoping that this water change will stop the disease and cure the ones that are infected. Too soon to tell at this point.

1/29/16: See Opae’ula Bubble Trouble Solved.

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15 Responses to Weird Bubble Growth on Opae’ula Shell

  1. Odin says:

    They look like air bubbles, I know they are not but I have never seen these before either, I’d just do exactly as you say and do a 50% water change.


  2. Anonymous says:

    Thanks, Odin. That was my first thought — air bubbles. But I’d never seen air bubbles on them before. I thought I saw a few bubbles escaping from one of the opae, but I’m not sure if it was from the body bubbles. On those affected, they first appeared as a tiny diamond on the underside, at about midway along the length of the body. At first, I thought it was the first stage of pregnancy. But it was occurring among younger opae, too, so I ruled that out. Also, I began to see this shiny speck of light on other parts of the body. I’m leaning toward a water change, and your idea of 50% makes sense. -Jim


  3. Robin says:

    So I went and refreshed my memory re Gas Bubble Disease in fish to see if there might be similarities in the tank parameters. Amazing how, still, there are a berjillion different answers for the same thing. UGH. But one of the common threads is high nitrates and rapid algae growth for causing gas saturation. One site even mentioned sunlight hitting the tank can exacerbate the problem. Is this one of your tanks that gets sun? I have zero idea if this will help re the shrimp, ’cause as you noted, there’s nothing on them having this. Just winging it here.

    These shrimp are tough, but with all the debris you said is in the tank your osmotic pressure might be up and I’d be worried that too many 50% water changes made at once, instead of over several days, might stress them or even kill them.

    I don’t know if molting will help them or not, or maybe even make this worse, but you could try putting some kelp (iodine) in there for them to eat in case they might want it.

    Best wishes and good luck!


    • JimS says:

      Thanks, Robin.

      I’ll read up on Gas Bubble Disease.

      Good point re too many water changes too soon.

      Re sunlight — this is occurring in my 10-gallon, which is farthest from direct sunlight and receives only a little in late afternoon. But it does have rich algae growth that requires cleaning every few months or so. I also use the LED light on overcast days and sometimes leave them on for part of the night.

      I haven’t been using a test kit but will be getting one soon to test for nitrate levels.

      I started to net some of the diseased opae and now have four in a 1-gallon quarantine bottle. Isolating and catching them is difficult, so it’s probably going to take me a while to remove some or most.

      Now that I’m observing them more closely, I’m finding that, for most, the bubble is in the abdomen area, on the underside where the front swimmerets (pleopods) are. I’m also beginning to see that the bubble makes it difficult for some of them to swim, exerting relative force in floating them toward the surface — a force that they have to oppose with some effort. They seem to free float every once in a while, like a balloon in the wind.



      • Robin says:

        Netting them. Oh. Yay. Good luck with that. 😦

        Have you got a good magnifying glass? Something occurred to me later. Could there be a parasite living in that bubble? They do sometimes with fish. Again, just winging it here. Have you brought in outside water or rocks? Something that could have had a hitchhiker in it? You’ve been doing this a while successfully. It just seems strange that this should just pop up like this.


  4. JimS says:

    Hmm. Parasites makes sense. I’m thinking back to see if I’d accidentally introduced them into the tank. Since I got the coral pebbles from the seashore, I rinsed and boiled them for an hour or more before using them. I did the same in my other tanks and haven’t had this problem — at least not yet.

    The gravel and UGF — I rinsed before using. I don’t feed them, so no contamination from food. Water for topping off is bottled. I rinse my hands and lower arms before I do any glass cleaning. I use the same pad for cleaning, and I rinse it before use.

    This tank has been stable and healthy for over a year (started 11/19/14), and nothing new has been added for at least a year. No new opae have been added in that time.

    One thing I’ve done, almost without thinking, is push salt that’s crusted on some edges of the tank back into the tank. These are small amounts, but I wonder if this could have inadvertently introduced parasites or chemicals that got mixed in with the dried salt.

    I’m guessing that the debris (waste) accumulation in the coral condo became a breeding ground for something that’s causing the bubble growth. I had assumed that the UGF was pulling the waste throughout the condo down into and through the gravel, keeping the condo relatively clean. However, I’m learning that the condo retains a lot of the debris, and it builds over time.

    If this is the case, then a flushing every few months or so followed immediately by a 50% water change may be the answer. The frequency of flushing would depend on the quantity of debris.


    • Robin says:

      It doesn’t sound as if you introduced anything to your tank. And pushing salt back into the tank is something every aquarist with salt water does, so if there was a problem with that I think it would be in the public domain by now. *shakes head*

      You mentioned below that introducing the filter may have upset things, but others have had filters with no issue. And the anchialine ponds have some circulation as well. I think this comes back to something going on with the water chemistry. An upset of some kind.

      So here’s another thought. Are you sure the bubbles on the shrimp you removed have gone? If so, maybe this -is- something related to the nitrates. The debris in your coral may be decaying and contributing to the nitrate level too quickly and there might not be enough algae in your tank to remove it from the water. The nitrates in the isolation jar would be fairly stable, or declining if there is algae, because of the lack of debris. What do you think? Yes? No?

      I know I’m floating a bunch of stuff your way, but, yes, selfishly, I hope if you figure out what is going on with your tank it might help me avoid the same issue with mine. Good luck!


      • JimS says:

        My choice of isolation container was poor. It’s plastic, and the surface is also grooved every inch or so. A lot of distortion. But I can see the underside of the opae when they crawl by. I don’t see the bubbles, but while trying to net them in the 10-gallon, I noticed that the overhead light made a difference. To get into the tank, I had to move the light to the front edge, and from this position, the bubbles were difficult to detect. Thus, until I can get a better look in better lighting, I’ll have to say that I really can’t tell if the bubbles are gone.


  5. Odin says:

    Don’t no worried about water changes affecting the shrimp, when I was keeping the nitrates down I was doing a 50% water change every 2 days for around a month and a half until it fully cycled and I didn’t loose one shrimp. Just make sure you match the SG in the clean water to the tanks SG.

    I know these are low maintanence but you should test the water with a test kit every week or so 🙂


    • Odin says:

      Checking Nitrites* not nitrates sorry.


    • JimS says:

      Thanks Odin. I’ll need to replace the idea of “no maintenance” with “low maintenance.” I’m guessing that introducing a filter into the mix somehow upsets the balance that purists achieve in their no maintenance no-filter tanks. How or why, I’m not sure. Currently, I’m sitting and waiting, observing the opae in the 10-gallon and in the 1-gallon isolation jar. The ones in the isolation had bubbles on their shell but are doing fine. They’re active. If I’m not mistaken, their bubbles have disappeared. The jar is made of clear plastic so it’s not as clear as glass. In the 10-gallon, the colony seems to be doing fine. No fatalities. I’m going to try and move more of the infected ones into the jar. -Jim


  6. JimS says:

    Bought a Tetra EasyStrips 6-in-1 test kit this afternoon. Dipped a strip and matched the results with the saltwater chart. These are the readings:
    Nitrate = 20
    Nitrite = 0.5
    Total Alkalinity = 60
    pH = 8.0
    Question: Do I need to “adjust” the chart for brackish water?
    Based on the saltwater chart: Nitrate level seems fine. Nitrite level seems a bit high. Total alkalinity should ideally be between 180-300, so 60 is very low. Yet pH level of 8.0 is in the acceptable range.
    Question: Do these results point to a possible cause of the bubble disease?


    • Robin says:

      Before I got my shrimp I was checking out testing kits. Was I really going to have to buy more kits? I found a guy on youtube who took the freshwater and saltwater kits and tested both a freshwater and saltwater tank. Results in the tubes were identical. The only difference was in the charts that came with the kits. The saltwater breaks the ‘colors’ into smaller increments. So, no, you don’t have to make adjustments.

      Can I assume your ammonia is zero? If you have a nitrite reading over zero, you either have ammonia fluxuations or you’re having problems with the bacteria that eat the nitrite. Possibles that pop to mind are the usual – not enough oxygen, low PH, which are not a problem here, and too cold water or low phosphates. I’m sure there might be others, but that’s what comes to mind.

      The 8.0 ph vs 60 alkalinity could be that your water has that much buffering capability, which is running out, but didn’t you say you used bottled water? If it is distilled, it wouldn’t have any buffers, etc. and the ph is due to the ‘ocean’ water. Your nitrates aren’t ‘bad’ so it isn’t acidifying your water and dragging the ph down, yet. Somewhere in the back of my mind, I want to say 50 or below on your alkalinity would be bad for the nitrification bacteria.

      But what does this have to do with your bubble disease issues, if anything? You know? I would love to have access to all the other peoples’ tanks, especially the ones who do nothing to their tanks, to see how everything compares. I didn’t even think about alkalinity till you brought it up. I do frequent water changes on my freshwater tanks, so it has never been an issue. Just didn’t occur to me. But what about the tanks where nothing is done? The alkalinity can’t last forever in those tanks, yet the shrimp survive. It just makes me realize all the more just how tough these little guys are. Yeesh.


      • JimS says:

        Thanks for the think-throughs with the data. The fact that no one’s published anything about this “disease” affecting opae’ula is interesting. Btw, I’ve been using bottled water — not distilled water, and I’m beginning to wonder if this might be the agent. I’ve been using a wide range of brands, opting for whatever’s on sale. But my primary source has been 1.5L bottles of “Hawaiian Isles: 100% Hawaiian Purified Water” from the local Sam’s Club. Not sure what “purified” means.

        Edit: Forgot to mention. I can’t recall where, but I thought I read somewhere that once a tank is cycled and established, the water quality tends to remain constant. But I’m not sure if the reference was to larger tanks only. This might explain why a lot of the no-maintenance unfiltered tanks survive for so long. Could it be that, for sustainability, there’s a bottom line for tank size?


  7. Robin says:

    Yeah, I’d be reading the label on that water and/or checking out their site to find out about what they’ve actually done to it. Have I mentioned I’m a critteraholic? I ran across some Triop eggs about three? weeks ago and remembered how much I’d enjoyed them when the kids had them. So I went to see what I could find out about them online since it’s been a few years. 🙂 Well, part of the Triops Learning Experience is all the “discussions” about water. Which is best for hatching, growing, storing eggs, etc… I found out, to my huge disgust, that you can slap a ‘purified’ label on just about anything. And a lot of those ‘purified’ and ‘spring’ waters have additives to make them taste better. (Yes, you actually have to find ‘spring’ water that actually does come from a spring. ‘Cause they can just add minerals to water and label it ‘spring water’.) Reading labels in a local store here I found one that clearly stated they had simply taken the water from a certain town’s municipal supply. And, yes, tap water is considered ‘purified’. Talk about your loop holes. I sure as heck know now what I WON’T be buying when it comes to bottled water. So, absolutely, check out that water! Of course, it comes back to if you’re using the same water for all your tanks, why is only the one tank affected?

    As for the tanks, water quality is never constant because critters and plants grow, using up nutrients and excreting waste. (Think about your freshwater tanks, the PH can fluctuate just depending on what time of day it is.) What larger bodies of water are good at are more stable water conditions with fewer large fluctuations. It takes a longer time for a situation to get critical in a larger volume of water giving aquarists time to correct the changes. Hopefully. (I could go on a rant here about our oceans, but I will restrain myself mightily. 🙂 )

    I think one of the main reasons the no-maintenance tanks succeed is do more to the shrimp than the size of the tank.The reason these shrimp are ideal for the ecospheres is because they control themselves in the environment. If the conditions aren’t good enough, they simply won’t breed. If the nutrient level goes down, they molt into a smaller body size and eat their molt for the nutrients. Shrinking themselves for survival.* In the no maintenance tanks, the populations seem to stay at just the right size for the available food supply. And we know how tough these guys are about adapting to all the changes in their water supply. I guess this just comes back to what in the heck is different about that one tank of yours?

    * I must confess past ownership of these ecospheres and have witnessed the shrink thing for myself. I didn’t know what was going on at the time and got real excited ’cause I thought the shrimp were making babies. Only I still had the same number of shrimp. It makes me sad every time I think about it. It wasn’t till I was wishing for another ecosphere, but didn’t have the money, that I got on the internet looking to see if I could get ‘just’ the shrimp and discovered what I’d done. 😦


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