Velvet & TT

[HumbleFish]

Paging Mr. Norvich

I've read where you say that a small percentage of fish can develop temporary (six months) immunity to velvet but are still carriers of it. So let's say I did TT on a fish, followed by one month observation to watch for symptoms of velvet & other diseases. A month goes by, I never see symptoms of velvet, so I add the fish to my DT. Next thing I know, bam! I've got velvet in my DT.

Am I understanding correctly? Would prophylactically treating with copper or CP (for a month after TT) be the only way to alleviate this threat? Or would running two or more fish thru TT, and then observing together for one month be the best strategy? As it would be highly unlikely that more than one fish would enjoy immunity?

 

[Newsmyrna80]

You seriously got velvet in your main? Would this mean that all fish in your DT had immunity? I'm interested in what Steve has to say as well. I'm running a couple of clowns through TT right now so I'm following along.

 

[snorvich]

If you happened to purchase a fish that had developed immunity to velvet it could bring velvet with it as a carrier, and it would not show up during TT or the period of observing following TT. In my experience, only fish that have been in an environment with active velvet can develop immunity, and again from my experience the percentage of fish that do so is about 5%. (I have not seen that percentage in the marine biology literature, however) Now that does not mean that a fish coming from a non-therapeutic dosing environment that masks velvet has immunity. It has been my experience that it will always show up during the observation period following TT.

 

[HumbleFish]

You seriously got velvet in your main?

No, I'm just trying to tighten my QT protocol.

If you happened to purchase a fish that had developed immunity to velvet it could bring velvet with it as a carrier, and it would not show up during TT or the period of observing following TT. In my experience, only fish that have been in an environment with active velvet can develop immunity, and again from my experience the percentage of fish that do so is about 5%.

^^This 5% is what I'm concerned about, not the ones with "masked" velvet that should show during the 1 month observation. What to do about the ones that develop immunity? If only TT is used and no chemical treatments?

 

[Newsmyrna80]

Oh ok, good Is there any scientific literature that a fish can develop immunity longer than 6 months?

 

[snorvich]

Oh ok, good Is there any scientific literature that a fish can develop immunity longer than 6 months?

The marine biology literature indicates six months. However, the caveat I would add is that there are multiple strains (of cryptocaryon irritans) so it is unclear if immunity covers all of them.

 

[snorvich]

^^This 5% is what I'm concerned about, not the ones with "masked" velvet that should show during the 1 month observation. What to do about the ones that develop immunity? If only TT is used and no chemical treatments?

I restrict my sources, but other than that, I do not know of any good way. Copper and as far as I know, CP, only work on one stage of the life cycle.

 

[Newsmyrna80]

If you happened to purchase a fish that had developed immunity to velvet it could bring velvet with it as a carrier, and it would not show up during TT or the period of observing following TT. In my experience, only fish that have been in an environment with active velvet can develop immunity, and again from my experience the percentage of fish that do so is about 5%. (I have not seen that percentage in the marine biology literature, however) Now that does not mean that a fish coming from a non-therapeutic dosing environment that masks velvet has immunity. It has been my experience that it will always show up during the observation period following TT.

Given this how prevalent is velvet in the ocean? Since the diseases aquarists commonly deal with are not as easily transmitted (for obvious reasons) in the wild I'm wondering how a fish could build up an immunity? Unless the immunization begins after being caught and going through the various stages of transport to the LFS.

 

[snorvich]

Given this how prevalent is velvet in the ocean? Since the diseases aquarists commonly deal with are not as easily transmitted (for obvious reasons) in the wild I'm wondering how a fish could build up an immunity? Unless the immunization begins after being caught and going through the various stages of transport to the LFS.

Parasites are a disease of confinement. The ocean, where fish move around (a lot) rarely contract parasites. The immunization process develops after capture when they are exposed to the contagious stage of the life cycle.

 

[HumbleFish]

So just to add, I read this in an abstract:

Histone-like proteins in the mucus and skin of naturally resistant fish kill trophonts of A. ocellatum, and also may cause abnormal development of tomonts.

I take this to mean that theronts are still able to infect, but then these "histone-like proteins" are zapping the trophonts before they can do any damage. So the fish never shows any signs/symptoms.

Source: http://www.ncbi.nlm.nih.gov/pubmed/18410078

 

[snorvich]

So just to add, I read this in an abstract:



I take this to mean that theronts are still able to infect, but then these "histone-like proteins" are zapping the trophonts before they can do any damage. So the fish never shows any signs/symptoms.

Source: http://www.ncbi.nlm.nih.gov/pubmed/18410078

"Naturally resistant" and "temporary immunity" are not the same as far as I am concerned. However, you may be right.

 

[HumbleFish]

It just seems like encountering a "velvet immune" fish is one downside to TTM, and presents a strong argument for prophylactically treating with CP or copper.

I like TTM A LOT, so I'm just trying to figure out a way to close this one loophole.

 

[snorvich]

It just seems like encountering a "velvet immune" fish is one downside to TTM, and presents a strong argument for prophylactically treating with CP or copper.

I like TTM A LOT, so I'm just trying to figure out a way to close this one loophole.

I doubt that prophylactic treatment with either CP or copper will solve that particular problem. I also highly doubt you will ever actually run into that circumstance; I feel it is much less than a 1% issue. (I only treat prophylactically with Prazi). However, the odds of running into the non-therapeutic masking of either crypto or velvet is IMO, fairly high, probably on the order of 10%, especially with certain species such as butterfly fish.

 

[HumbleFish]

I doubt that prophylactic treatment with either CP or copper will solve that particular problem. I also highly doubt you will ever actually run into that circumstance; I feel it is much less than a 1% issue. (I only treat prophylactically with Prazi). However, the odds of running into the non-therapeutic masking of either crypto or velvet is IMO, fairly high, probably on the order of 10%, especially with certain species such as butterfly fish.

Steve, thank you very much for your input.

One last question... Would it be wise to QT (and run thru TT) always at least 2 fish together? My reasoning is if a natural resistant or temporary immune fish were encountered, the other fish should be the one to show symptoms.

 

[snorvich]

Steve, thank you very much for your input.

One last question... Would it be wise to QT (and run thru TT) always at least 2 fish together? My reasoning is if a natural resistant or temporary immune fish were encountered, the other fish should be the one to show symptoms.

Well, you could keep a "canary" fish that is used only to detect danger (like miners used to do) but where would you keep it when not "in service"?

 

[HumbleFish]

Well, you could keep a "canary" fish that is used only to detect danger (like miners used to do) but where would you keep it when not "in service"?

I was thinking more along the lines of always buying/QT'ing/TT'ing fish in at least quantities of two.

 

[GroktheCube]

It definitely can make life easier to QT multiple newcomers at once, but also raises the chances that you will have multiple diseases to deal with. Ask me how I know

I think it's very unlikely a fish with velvet will sneak by TTM plus a few weeks of observation/deworming. That's one reason I tend to deworm AFTER TTM, unless I see a fish with severe gill fluke infestation.

It'd be extraordinarily rare for a fish to go 4-6 weeks in QT without showing symptoms of velvet or brook if present.

 

[snorvich]

I was thinking more along the lines of always buying/QT'ing/TT'ing fish in at least quantities of two.

No. Think about it. First you could in theory have two different diseases/parasites. Secondly, unless you have a known "healthy canary", the risk is still present.

 

[HumbleFish]

It'd be extraordinarily rare for a fish to go 4-6 weeks in QT without showing symptoms of velvet or brook if present.

Oh, I know. I'm just trying to fine tune my QT regimen.

No. Think about it. First you could in theory have two different diseases/parasites. Secondly, unless you have a known "healthy canary", the risk is still present.

I guess I figure if the odds are so low of acquiring one immune specimen, then the odds of getting TWO (at the same time) are probably next to impossible. I suppose a better option would be to always keep a chromis in QT as the "healthy canary". A "black canary" would work better though (to see ich/velvet). Those are the two diseases I'm mainly worried about "missing" when doing TT. Murphy's Law, ya know?

 

[GroktheCube]

Oh, I know. I'm just trying to fine tune my QT regimen.



I guess I figure if the odds are so low of acquiring one immune specimen, then the odds of getting TWO (at the same time) are probably next to impossible. I suppose a better option would be to always keep a chromis in QT as the "healthy canary". A "black canary" would work better though (to see ich/velvet). Those are the two diseases I'm mainly worried about "missing" when doing TT. Murphy's Law, ya know?

What he means is that with two fish, the odds of having two (or more) diseases to treat are increased.

I recently broke down my 120 and took out all of my fish to treat for ich (introduced via un-QTed inverts) via TTM.

There were a few more fish I wanted to add, so I decided why not do them at the same time?

Problem is, one of the new fish was carrying velvet.

I was VERY lucky to have been cycling an HOB for use on the tank they were going to sit in during fallow time, as that allowed me to do an FWD into a tank with an adequate biofilter to support them and thus allow for cupramine, but still had a couple losses.

I have some new fish coming in tomorrow morning (3 female P. lineopunctatus), and they WILL be going into their own QT until I'm quite confident that they are disease free.

Lesson(s) learned:
1. QT your damn inverts too!
2. Adding several fish of unknown health/disease status to a tank with fish of known health/disease status is begging for trouble.

Honestly, if you're THAT worried about a fish being adequately velvet resistant that it could slip through observation (quite unlikely IMHO), I think you'd probably be better off treating prophylactically with copper or chloroquine.