Velvet dormant in tank for a year?

[SMR45]

What you are saying makes sense. I just can’t figure out how it may have gotten in the tank. Have you ever heard of it being in commercial food cubes? I use San Francisco Bay Brand cubes and Pro Salt clams.

[Sk8r]

I would agree.

[SMR45]

What you are saying makes sense. I just can't understand how it got in there though. Have you ever heard of it being in commercial food? I use the San Francisco Bay Brand cubes and Pro Salt Clams.

[Dmorty217]

Fresh mussels or clams could potentially bring it into a tank but not frozen cubes. I mean I suppose it’s possible but companies would go out of buisness quickly if disease is in their food

[ThRoewer]

Originally Posted by Dmorty217

Fresh mussels or clams could potentially bring it into a tank but not frozen cubes. I mean I suppose it’s possible but companies would go out of buisness quickly if disease is in their food

One reason why I prefer feeding mysis. Those are collected from freshwater lakes.

I'm not sure if there has ever been a study done if Cryptocaryon and Amyloodinium cysts can survive being frozen but I would not rule out the possibility. Cryptocaryon cysts can for sure survive cold water temperatures in a state of hibernation and produce infectious stages when the temperature rises above 19 °C again.



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[HumbleFish]

The truth is we do not know if freezing makes tomonts not viable. Or at least I've never seen a study on that. I know LRS has mentioned deep freezing their food @ -24F, possibly to kill off any pathogens? But even -24F must not kill all bacteria because they tout that their food contains probiotics.

[SMR45]

Thank you again for everyone who responded - I sincerely appreciate all of the reply's and help/advice.

Can you advise on what food you consider safe from pathogens? I only use the frozen food i mentioned - nothing fresh. I will certainly switch sources if that will help prevent this from ever happening again. And I can confirm that this did come on quickly and devastatingly fast.


Update: all of the remaining surviving fish are still ok and starting to eat a little more. Keeping cooper levels at 2.0 to 2.2

[ThRoewer]

While the food can't be completely ruled out as a source of this infection I would say it is rather unlikely. Far more likely is that this came in on a more common way. IMO one of the more likely paths is that your friend, when he worked on your tank, had a cyst or flagelat from another tank on him that escaped all scrutiny and made it into your tank.

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[SMR45]

I agree the frozen food seems improbable. I just thought I would ask in case anyone had heard of it happening. It's possible it came inadvertently from my friend. It has been about four months since he was here though. My past experience with velvet was pretty immediate. I introduced the new fish, saw symptoms within a few days and had fish dying within a week or so.

This time was fairly immediate as well. Everything was fine until it wasn't - there wasn't much warning. Yes, I should have realized what is was sooner but it happened quickly.

One bit of good news is the remaining fish seem to be healing and all ate pretty well today. This isn't over but I'm now cautiously optimistic regarding the survivors. Again, I do appreciate all of the help and responses.

[ThRoewer]

4 months sounds too long for Velvet.
Are you sure it is Velvet? Cryptocaryon would fit better as that one is known for being able to lay dormant for months, even up to a year under the right conditions.

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[SMR45]

I'm almost positive it's velvet. I agree Ich would fit better but it's usually not lethal so quickly. I first noticed obvious symptoms on my Bluering about two weeks or so ago - fine sugar like speckles that covered it's entire body. No obvious white spots, just the covering that could only be seen in certain light/angles and it had a sheen. The mimic tang didn't have the speckle covering that I could see but he was not as active and wasn't eating as much. I saw them both in front of my wave maker at times but still thought it was ich at the time. Next I noticed my Kole tank in front of the wave maker and observed the sugar like speckles and sheen to him as well. Again in certain light I could see it but in other light he looked ok. He was the first to die and the others followed quickly afterward. During this time I also noticed my black cap basslet wasn't coming out of his rock as much. He died quickly as well but I didn't see anything on him.

Does this help? These fish did not have a white spot or mark on them prior to this starting. I observe them every day for behavior and/or eating changes.

[SMR45]

My lemon peel only showed signs at the very end (that I saw). My watanabe showed no signs that I observed until I found her gone that same evening.

All of the deaths happened within 60 hours (2 1/2 days) or so.

[ThRoewer]

Yes, that sounds like velvet. Ich symptoms are usually quite obvious and white spots (their size actually depends on the fish species and how the fish's skin reacts to the irritation the parasite causes) are generally visible even at very early stages. Research has shown that the locations of the infections are fairly random and nearly equally likely on the entire body with only a slight preference for the gills.
Velvet, on the other hand, targets the gills and can be fairly confined to just the gills. By the time you see the velvety golden coating on the body, the infection is already quite advanced.

Acquired immunity to amyloodiniosis is associated with an antibody response

https://www.researchgate.net/publica...e_earthen_pond

"... Moreover, the study of immune hosts showed that after a sub-lethal exposure to the parasite some fish species acquire immunity which is mediated by specific antibodies (Smith et al, 1994; Cecchini et al, 2001). ..."

http://repositorio.furg.br/xmlui/bit...pdf?sequence=1

"... Infested fish were successfully treated with copper sulfate (1.5-mg CUn for 24 h during 7d). Observation of the biofilm from the bottom of the tank showed a high number of resting cysts (tomonts) of A. cf. ocellatum after treatment. Apparently, the copper sulfate forced the detachment of the trophonts (feeding parasitic growth stage), and generated the high number of tomonts at the bottom of the tank. The copper sulfate concentration used in the treatment was not effective to kill the tomonts. ..."


Those articles could give some possible explanations for what happened.
But from everything you described a re-introduction close to the outbreak is far more likely than the parasite lying dormant for a year or being present and active while the fish were partially immune to it.

Below a few more articles that may shed light on Amyloodinium and fish's immunity to it

Studies on Amyloodinium ocellatum (Dinoflagellata) in Mississippi Sound: natural and experimental hosts

Reproduction cycle and tolerance to temperature and salinity of Amyloodinium ocellatum (Brown, 1931)(Dinoflagellida).

Amyloodinium ocellatum (by E.J. Noga)

[SMR45]

Thank you for providing all of the links and info. I read all of the articles with the exception of the last one, Amlyoodinium Ocelliatum by EJ Noga. That one gave me page no longer available error.

I do have a new understanding of velvet, it's lifecycle and potential immunity. For example, my ocellaris clown pair showed no signs of the disease this time or the first (they have been with me for about 10 years now, first in my 55 gallon and than the 180 gallon upgrade tank about a year later). One of the articles spoke about immunity for tomato clown fish but maybe some other species of clowns also have immunity. Mine are tank bred.

Second thing I learned from the articles: After copper treatment trophonts detach and become tomonts and stayed adhered to biofilm at bottom of tank or substrate.

This got me to think about one thing I did differently in my tank maintenance the past few weeks. My rock is not positioned directly against the back tank wall but has several inches clearance. I set it up this way deliberately so the fish would have more swimming room and can make complete circles around the rock and tank if desired.

I vacuum my sand bed weekly during water changes in front, sides and back corners, but can't reach the middle back easily. The last few weeks I have disturbed the middle back sand bed a bit (not completely) to try and get at some nuisance algea I wanted to get rid of. Note my sand bed is not deep - maybe an inch around, less in areas. And I have disturbed the back before - just not recently.

Question: Could a tomont survive that long in the sand bed and initial copper treatment and infect my fish now?

[ThRoewer]

Originally Posted by SMR45

...with the exception of the last one, Amlyoodinium Ocelliatum by EJ Noga. That one gave me page no longer available error.

Strange, the link works fine for me.
Try to get it from Google Scholar by using the link below or searching Google Scholar with the following: "Amyloodinium ocellatum Edward J. Noga"

https://scholar.google.com/scholar?h...+J.+Noga&btnG=

The PDF from academia.edu should contain the whole book.

Originally Posted by SMR45

Question: Could a tomont survive that long in the sand bed and initial copper treatment and infect my fish now?

Your guess is as good as anyone's on that one. It seems no one really looked into the possibility of Velvet laying dormant for extended periods of time yet.

[ThRoewer]

I found a study done on cryogenic preservation of Amyloodinium ocellatum.

Studies on the cryopreservation and in vitro culture of Amyloodinium ocellatum [2006]
Yang, Chu-Ya Cheng-Fang Chang [Corporate Author] Li-Lian Liu [Corporate Author] Shih-Chu Chen [Corporate Author] Jung-Pin Hsu [Corporate Author]

The Amyloodinium ocellatum was collected from cobia ( Rachycentron canadum ) gill and four tests including 4 ¢J storage, toxicity of cryoprotectant, cryopreservation and in vitro cultivation on fish cell line were conducted to establish the methods of preservation of Amyloodinium ocellatum. Survival of trophont, morphology and division of tomont and number of dinospore released were evaluated the effects of this study. The results showed that division irregulated, delayed and stopped of the tomont were found after stored at 4 ¢J over 48 hours. It was produced 1.08 x 10 4 cell/ml dinospores from 1 x 10 3 trophont at 4 ¢J, 24 hours storage group and significant higher ( p¡Õ0.0001 ) than other storage groups. For the toxicity of cryoprotectant, the concentration of DMSO 3~10¢M, Glycerol 3~10¢M, Methanol 3~10¢M, Ethanol 3~5¢M, PrOH 3~5¢M, DMAc 3~5¢M, Sucrose 3~15¢M, Trehalose 3~15¢M, Dextran 3~5¢Mand Ficoll 3~10¢Mwere safety to use on A. ocellatum trophont preservation. It was unsuccessful to cryopreserve the trophont of A. ocellatum when stored at direct liquid N2 freezing, different -20 ¢J freezing time, -1 ¢J min-1 freezing container and different cryoprotectant equilibration time contain 10¢MGlycerol and DMSO, respectively. Using the U-shaped tube of sigle and double loop could gain pure and bacteria-free dinospores. The results of in vitro cultivation of A. ocellatum showed that eel epidermis and cobia fin cell line with different culture mediums were unable to grow the trophont and tomont of A. ocellatum.

What I extract from this is that the frozen Amyloodinium stages were not viable after being unfrozen. This suggests that propagation via frozen food is highly unlikely.

[ThRoewer]

Seems combining hyposalinity and copper treatment increases treatment success:

Amyloodiniosis in cultured Dicentrarchus labrax: parasitological and molecular diagnosis, and an improved treatment protocol

ABSTRACT: Amyloodinium ocellatum, the causative agent of amyloodiniosis (marine velvet, velvet disease), affects marine and brackish fish in various warm and temperate habitats. We recorded disease outbreaks with high morbidity and mortality rates in marine-cultured European seabass Dicentrarchus labrax fry at 2 locations in northwest Egypt. The sudden outbreak, high morbidity and mortality rates, and skin lesions with a velvety appearance in affected fish all indicated A. ocellatum infection. This was further confirmed by microscopic findings of the parasitic stage (trophonts) in skin and gill smears. While ecological factors including water temperature and salinity were all amenable to parasite establishment and propagation, mortality rates differed between the 2 farms, with rates of mortality well correlated with prevalence and intensity of A. ocellatum infections. Characterization by PCR targeting rDNA gene fragments and subsequent DNA sequencing and phylogenetic analysis further confirmed the molecular identity of the A. ocellatum isolate, which was genetically similar to isolates from other geographical locations. Finally, an improved treatment method using dual hyposalination and copper sulfate exposure to increase the efficiency and decrease the toxicity of copper sulfate was tested. The gradual reduction in water salinity coupled with copper sulfate treatment was more efficient at controlling the disease than only applying copper sulfate. To our knowledge, this is the first parasitological and molecular characterization of A. ocellatum in marine cultures in Egypt. The high molecular identity and close phylogenetic relationship further confirmed the monophyletic nature of A. ocellatum isolates.

[SMR45]

I did find the article from Noga and reading the rest now...

[ThRoewer]

Originally Posted by SMR45

I did find the article from Noga and reading the rest now...

BTW, have you been to a fish store within weeks before this started?
Any visitors who have tanks?
What about fish for eating? Bought any fresh fish from the grocery store and then worked on the tank?
Have you or anyone from your house been to the ocean or a brackish pond, river,...?

[jjencek]

The signs do sound like velvet, but is there any chance we can verify it to make sure we are talking about velvet? Any possibility of lab tests?

[ThRoewer]

Originally Posted by jjencek

The signs do sound like velvet, but is there any chance we can verify it to make sure we are talking about velvet? Any possibility of lab tests?

Lab tests are tricky and usually require to send in a living fish that is infected but not too severely so that it can survive shipping. But first you have to find a lab that can do the test and is accepting samples from hobbyists. Easier said than done.
The golden to rusty velvety shine at the right light and observation angles is usually definitive enough for us to call it and take the appropriate measures.
A microscopic or even genetic confirmation is mostly a concern if you want to publish a study about the parasite.

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[SMR45]

I don't know of any lab around me that would analyze the fish. The remaining have been in therapeutic levels of copper for almost nine days now so I would hope it's no longer in the gills.

As to your other questions:
-Before this happened my last visit to my LFS was probably two to three weeks prior. I can't remember the exact date but I go about once a month for food and this started about two to two and a half weeks ago.
-No visitors that I can think of that have tanks.
-Haven't bought fresh seafood from the grocery store in over a month or two. I do use frozen cooked shrimp regularly but if it can't be viable in frozen fish food I'm hoping it's not in human food. The tank is at the opposite end of the house from the kitchen and 99% of the time I wash my hands before and after putting them in the tank (leaving myself a bit of wiggle room there in case of a time I forgot).
-No one in the house has been to the ocean or brackish water. I live on the east coast so it's winter here and we haven't traveled.

[ThRoewer]

The timeline would fit for you to have brought it back from the fish store.

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[SMR45]

I'm open to any possibility and due to the timeline it could have happened. But it's kind of a scary thought that a trip to your LFS to buy food could bring this to your tank. I didn't touch any water while there but of course touched handles to open the food freezer and counter to pay. I do browse around the tanks a bit to see what's there.

I'm a bit of a germaphobe so one of the first things I do when entering my house is wash my hands. Is there any other way to transmit? I've read about aerosol transmission but thought that was for tanks close together.

[ronalvio]

This is terrifying


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