chromis viridis: bloody diagonal band on body -- fungus?

[pescadero]

I recently acquired a school of juvenile chromis viridis that developed a bloody diagonal band on their flanks just before they died. the mortality rate was high.

i seem to remember reading a post in this forum that mentioned that the chromis is subject to fungal infections, and that hyposalinity will augment the fungus' growth.

i've searched for more information about this subject but i have not been able to find it. i've also not been able to find the thread in this forum where i had originally seen this information.

any insights would be appreciated.

 

[sugartooth]

Are you keeping your purchases in separate QT systems or are they going all together in one large QT?

Was your QT set up brand new (purchased from a store) or used from a tank breakdown?

I ask because I had two separate QT systems that were not cleaned out properly and it seemed no matter how high the water quality, there would be casualties with subsequent fish. My disease were different than yours, but just wanted to rule out this as your source.

After my deaths, I poured 2 cups of bleach into each running QT, followed by a large water change 1-2 days following. I also put in Prime for the chlorine. I kept the system running for another week, then another large water change with polyfilters. I drained the tank and sprayed 90% Ethanol and wiped down.

Since then, all of my fish are doing well in both of these QT. I have no proof other than I had deaths before this cleaning.


As I understand, redness and streaks are mainly attributed to bacterial infections and ammonia or pH type burns. Fungus would be seen more as cotton or more fuzzy structures.


If you are keeping these fish in hyposalinity, you have adjusted the pH and alk accordingly, correct?


I'm not sure how far you are from the IL border, but if you ever get out to the far North suburbs, you are more than welcome to bring a scraping and have a look under a microscope to see what you are dealing with. I also have a number of medications in my first aid kit for a broad range of ailments.

Good luck.

 

[JHemdal]

pescadero,

Do the bloody diagonal lines run along the scale rows? Do you have access to a microscope? We have had quite a few groups of Chromis with the same symptom and it turned out to be Uronema protozoans. These actually do better at hyposalinity than at full (Although you will read that hypo is a treatment for this - I have a copy of the paper people extrapolated that from and the "hypo" salinity that was studied was 4 ppt - which is almost freshwater).
Uronema is very difficult to treat - high dose formalin baths are one possibility. Here is a confounding issue - Uronema normally feed on bacteria - so the lesions look just like bacterial infections and in fact, may have gotten their start as such. Its like the Uronema just don't know when to stop eating, and keep going after the bacteria are gone, right into the fish.
A microscope will also help you rule out a fungal infection, but true external fungal infections are virtually non-existant in marine aquariums anyway.


JHemdal

 

[pescadero]

<a href=showthread.php?s=&postid=12197495#post12197495 target=_blank>Originally posted</a> by sugartooth
Are you keeping your purchases in separate QT systems or are they going all together in one large QT?

Was your QT set up brand new (purchased from a store) or used from a tank breakdown?

every fish purchase goes into its own QT system. i have 5 QT systems running right now. each of them is a used tank that had been bleached and left dry for 8 weeks before being filled with water for the QT. i don't think that the QT system is acting as a vector to introduce disease into the fish, but thanks for suggesting that.

If you are keeping these fish in hyposalinity, you have adjusted the pH and alk accordingly, correct?

yes.

and thanks for the offer to help.

 

[pescadero]

<a href=showthread.php?s=&postid=12198222#post12198222 target=_blank>Originally posted</a> by JHemdal
pescadero,

Do the bloody diagonal lines run along the scale rows? Do you have access to a microscope? We have had quite a few groups of Chromis with the same symptom and it turned out to be Uronema protozoans. These actually do better at hyposalinity than at full (Although you will read that hypo is a treatment for this - I have a copy of the paper people extrapolated that from and the "hypo" salinity that was studied was 4 ppt - which is almost freshwater).
Uronema is very difficult to treat - high dose formalin baths are one possibility. Here is a confounding issue - Uronema normally feed on bacteria - so the lesions look just like bacterial infections and in fact, may have gotten their start as such. Its like the Uronema just don't know when to stop eating, and keep going after the bacteria are gone, right into the fish.
A microscope will also help you rule out a fungal infection, but true external fungal infections are virtually non-existant in marine aquariums anyway.


JHemdal

as it turns out i do have a 40-400x medical microscope that i have not used in decades. its no problem to put it back in service, but i have to admit that i am not set-up to process tissue specimens -- i don't have a freezing microtome and i'm not set up to do anything like gram staining, H&E staining, or bacterial C&S. the only thing that i could do at home is to dissect out a piece of tissue/organ and do a squash mount.

i took the chromis and put them into the deep freezer as i fished their corpses out of the tank. to examine them under a scope all that i would need to do is to thaw them.

i bought 20 of them from LiveAquaria.com last week when they were "on sale." of the 20 that were shipped in 4 separate bags, each bag contained fish that were old and dead -- stiff and stinky. with the rigor mortis having already set-in, i was wondering if they might have already been dead when they were put into the bag. i acclimated the rest of the fish to hypo at 1.020, and before going into the tank each fish got a 15-minute FW dip. i should have used formalin.

at 0 hours i had a school of 10 fish.
at 24 hours i had 5 fish
by 48 hours i had 0 fish

the fish initially appeared normal, but each fish gradually developed a bloody diagonal band running from the posterior dorsal fin, diagonally downward and rearward toward the caudal peduncle. the lesions looked like small traumatic hematomas, or subcutaneous hemorrhages. perhaps i can take some out of the freezer and snap a photo for you.

the fish arrived by FedEx on Friday and all of them were dead by Monday morning. i wonder if there was a problem with their stock that prompted a fire sale.

 

[pescadero]

<a href=showthread.php?s=&postid=12198222#post12198222 target=_blank>Originally posted</a> by JHemdal
We have had quite a few groups of Chromis with the same symptom and it turned out to be Uronema protozoans. These actually do better at hyposalinity than at full (Although you will read that hypo is a treatment for this

in saying that, do you mean to say that the Uronema protozoans do better at hyposalinity than at full strength seawater, or that chromis with the infection do better at hypo than at full strength seawater? Am I correct in understanding you to be saying that chromis with this infection will fare worse at hyposalinity because those conditions favor the pathogen?

I would be very interested in reading that paper.

 

[JHemdal]

pescadero,

No need to get too elaborate, a quick wet mount of a skin scrape from a fresh (not frozen) fish at around 50x will show Uronema if it is there. Once they are frozen you probably won't be able to find the Uronema.

What you are reporting is so much like our cases I would be really surprised if it turned out to be something else - but understand, I'm sort of building a "mind's eye view" based on how I interpret you messages - and there is always a tendancy for people to sort of "make" things fit better - like when you read your horoscope and it always seems spot on because you weed out the points that don't fit or make sense(grin).

For what its worth, in the most recent case I recall that even though I identified Uronema on the first fish that died, I couldn't stop it until just a couple of fish were left.

Yeah, if you've read my posts around here much, you'll know that I'm not big on hyposalinity (especially below 1.0125) because of the prevalence of Uronema. It is almost 100% misidentified as a bacterial infection, unless people have a scope. So; you get this scenario where somebody has some anthias or other sensitive fish in hypo to treat Cryptocaryon and then the fish develop these lesions and die and the people just write it off as secondary bacterial infections to the Cryptocaryon.
Its kind of strange how pervasive the hyposalinity treatment for Uronema has become. In 1985 we all knew to watch for it during hypo, then there were a series of popular articles a few years ago that touted this "cure" and now its all over the Internet - but sadly, it's incorrect.

JHemdal

p.s. - I should point out that we call this Uronema but it really is just a non-descript oval 40um motile ciliate, so more accurately, I should call it "Uronema-like" because I've never had it identified to species.

 

[FishTri]

As long as we're talking about Chromis...

I just acquired four from someone who tells me they purchased them three to four weeks ago from their LFS. I was excited because I figured at least these four made it past the first week when many seem to die.

However, when I went to pick them up, one of them had several large blotchy areas. The others seem normal, although there may be small patches starting to appear. I brought them home and kept them for a couple of days in a salt bucket treated with methylene blue. They've spent the last forty eight hours together in a ten-gallon quarantine tank.

They are active, and feed readily. Would you recommend a concentrated formalin dip, a prolonged low-dose formalin treatment in the quarantine tank, or some other measure(s)?

 

[pescadero]

<a href=showthread.php?s=&postid=12200232#post12200232 target=_blank>Originally posted</a> by JHemdal
No need to get too elaborate, a quick wet mount of a skin scrape from a fresh (not frozen) fish at around 50x will show Uronema if it is there. Once they are frozen you probably won't be able to find the Uronema.
...
For what its worth, in the most recent case I recall that even though I identified Uronema on the first fish that died, I couldn't stop it until just a couple of fish were left.

thanks again for your help.

After reading your posts I read the entry in Noga's Fish Disease: Diagnosis and Treatment related to Uronema. The symptoms he described (along with symptoms I've found listed online) are exactly those that I experienced, though I failed to mention all of them: color loss (some of the fish turned white), focal depigmentation, pitting, skin ulceration, dyspnea, tachypnea, hyperactivity, and lethargy. Granted, these are nonspecific signs.

Noga's book recommends freshwater baths followed by prolonged immersion in formalin, and mentions that this treatment is only useful in the early stages. Once enough organ/tissue damage occurs, the natural history of the disease is a rapid downward spiral that cannot be stopped.

in the Diagnosis section, the text mentions skin scrapings, just as you recommended. It also mentions that if a wet mount skin scraping is non-diagnostic then tissue histology may be needed for diagnosis. As I mentioned earlier, although I don't have a fully equipped path lab at home, I probably could to a squash mount of a gill and/or kidney tissue specimen. If the fish died of Uronema, I'm certain that the organisms would be visible there, hopefully even on a frozen/thawed specimen.

To answer FishTri's question: As far as treatment is concerned, Noga's book mentions treatment of the early stages with FW baths followed by prolonged immersion in formalin. Advanced lesions have been reported to respond to methylene blue or nitrofurazone, though systemic and deep tissue infections have a poor prognosis.

Of course, I have no experience in treating this disease, I'm just reading to you from a book.

JH, thanks so much for your help.

 

[pescadero]

<a href=showthread.php?s=&postid=12200232#post12200232 target=_blank>Originally posted</a> by JHemdal
Yeah, if you've read my posts around here much, you'll know that I'm not big on hyposalinity (especially below 1.0125) because of the prevalence of Uronema. It is almost 100% misidentified as a bacterial infection, unless people have a scope. So; you get this scenario where somebody has some anthias or other sensitive fish in hypo to treat Cryptocaryon and then the fish develop these lesions and die and the people just write it off as secondary bacterial infections to the Cryptocaryon.
Its kind of strange how pervasive the hyposalinity treatment for Uronema has become. In 1985 we all knew to watch for it during hypo, then there were a series of popular articles a few years ago that touted this "cure" and now its all over the Internet - but sadly, it's incorrect.

I'd really like to institute a well-devised treatment protocol for prophylactically treating all of the incoming fish, in order to eliminate as many virulent bacterial and/or parasitic organisms as possible before the fish are placed in my display aquarium. Yes, I am one of those people who would prefer to quarantine and prophylactically treat every incoming fish, rock, piece of macroalgae, etc., before adding them to my display.

The sources I have read have led me to believe that hyposalinic quarantine at 1.010 for a period of 6 weeks was actually the best way to approach the ich problem, especialy in copper sensitive species. hearing what you've said about Uronema, I guess tht this might not be the case. Perhaps it would be better to just treat the fish that aren't planned for breeding with copper at normosalinity.

Do you have any protocols that you have established for prophylactic treatment of all of the major diseases, prior to introduction to the display aquarium? I would expect that professional fishkeepers would have to have such protocols in place, its just that I have not enountered them. By any chance is this topic covered in Advanced Marine Aquarium Techniques? I have to admit that I am not familiar with book, though I am an avid reader and I am always interested in expanding my reference library.

Thanks again for your help.

PS - there's a typo in one of my earlier posts. when i accomodated the fish to hypo and did the 15 minute FW baths, the fish were acclimated to a s.g. of 1.010. the reference to 1.020 was a typo.

 

[JHemdal]

pescadero,

There was a unclear statement in my last post - so I wanted to clarify the "cure" I was talking about that doesn't work is not hypo for Cryptocaryon - we all pretty much agree that works, but rather hypo for Uronema. In my opinion, there is just an underated risk for inducing Uronema while treating for Cryptocaryon with hypo.....

I also treat prophylactically during quarantine for protozoans and metazoans (primarily flukes). I don't treat in advance for bacterial infections due to the risk of inducing antibiotic-resitant strains. Preventative quarantine is a controversial subject with many people, and I will admit that I use an "observational quarantine" on some specialized fish such as garden eels and flashlight fish.
People need to be aware that Noga's reference to using a FW dip is NOT an endorsement for hyposalinity treatment of Uronema.
Yes, my book has a section on quarantine protocols in it, the section starts off with, "Because of the cryptic nature of many fish diseases, ALL new fishes must be suspected of harboring either acute or chronic infections." So - you can probably see where that is going to go - grin. However, due to the scope of the book, this section is only about 5 or 6 pages long, so please don't think that it is an exhaustive treatment of this topic.
I'm working on the outline for a marine fish disease book (part of the reason why I've been more active on RC is to get a better feel for what problems home aquarists are experiencing right now).

JHemdal

 

[FishTri]

<a href=showthread.php?s=&postid=12201994#post12201994 target=_blank>Originally posted</a> by pescadero


To answer FishTri's question: As far as treatment is concerned, Noga's book mentions treatment of the early stages with FW baths followed by prolonged immersion in formalin. Advanced lesions have been reported to respond to methylene blue or nitrofurazone, though systemic and deep tissue infections have a poor prognosis.

Thanks for the response.

At this point there is no carbon or biologic filter running in the 10 gallon quarantine tank with the four Chromis. All four are still eating/acting healthy this morning but I'm thinking its best to treat the entire tank with an extended course of Formalin.

I'm off to read the instructions on the back of the bottle...

 

[pescadero]

<a href=showthread.php?s=&postid=12203213#post12203213 target=_blank>Originally posted</a> by JHemdal
There was a unclear statement in my last post - so I wanted to clarify the "cure" I was talking about that doesn't work is not hypo for Cryptocaryon - we all pretty much agree that works, but rather hypo for Uronema. In my opinion, there is just an underated risk for inducing Uronema while treating for Cryptocaryon with hypo.....

just to make sure that i'm on the right page then -- everyone agrees that hyposalinity at 1.010 for 6 weeks is highly effective for treating Cryptocaryon. The problem is that the transition to hyposalinity favors the growth of Uronema, and this transition can often induce a subclinical Uronema infection to become a clinical infection? Can you tell me the s.g. ranges over which the induction takes place? I think I remember you mentioning a paper that referenced that topic. I am serious that I would like to read that paper, so I'd appreciate any help that you might be able to offer in tracking down a copy, either with a citation or perhaps a reprint.

 

[JHemdal]

pescadero,

Right, MOST everyone agrees about hypo at 1.010 (but I use 1.0125 if I use it at all) you'll see Uronema growing exceptionally well between 1.006 and up to around 1.016. It can commonly be found at normal marine specific gravity, but some people have found that hypersalinity - up 1.028 starts to limit it's growth.
Uronema is a ubiquitous, falcultative parasite, and like I mentioned, probably gets is start feeding on bacteria at the site of an external lesion on the fish, and then just doesn't know when to quit - and keeps going on into the body of the fish. We've had it go systemic - infecting internal organs, the fish always die at that point.

You got to hand it to Ed Noga, he tries to cover all bases: "...hyperactivity, and lethargy..." as signs of Uronema! Both? At the same time? Or does the fish alternate?

JHemdal

p.s. - I looked for the article yesterday but I can't find it......

 

[pescadero]

<a href=showthread.php?s=&postid=12204665#post12204665 target=_blank>Originally posted</a> by JHemdal
...
Uronema is a ubiquitous, falcultative parasite, and like I mentioned, probably gets is start feeding on bacteria at the site of an external lesion on the fish, and then just doesn't know when to quit - and keeps going on into the body of the fish. We've had it go systemic - infecting internal organs, the fish always die at that point.

so it seems then, that hyposalinity treatment for ich is the equivalent of begging for a Uronema problem. this seems to be especially true in the juvenile chromis viridis, where they will beat up one another in competition for food and hiding places when transitioned to a new tank. the seemingly innocent fights lead to what might otherwise be insignificant wounds that would not cause a problem under normal circumstances. at hyposalinity, the wounds seem to be more likely to be ravaged by an opportunistic infection than at normosalinity. this is just my anecdotal experience, of course.

when you mention that Uronema is a facultative parasite, I'm not sure of how you're using the word facultative. i'm familiar with the use of the term faculative to describe bacteria that are not obligate aerobes/anaerobes (ie: facultative anaerobes). i'm just not familiar with the use of the term in other ways. in using the term facultative, are you referring to Uronema's ability to act as an opportunistic infection while facultatively adapting from normosalinity to hyposalinity? if that's the case then i do understand what you were trying to tell me.

my experience with juvenile chromis viridis has been that there is a high mortality rate when transitioned to a new tank environment. i read an article in the damselvishes edition of Coral magazine that the chromis viridis is famous for "thinning the herd" until only two fish survive. the article suggested that competition for food was the underlying cause, and that automated feeding q 15 minutes would eliminate the problem. I'm wondering if Uronema might be the underlying cause for the high mortality.

I've certainly seen the high mortality at hyposalinity. This makes me wonder what the best approach would be in quarantining and prophyllaxing these fish. For eradication of Cryptocaryon, I'm beginning to think that keepng the chromis at normosalinity and treating with copper might be the best approach to the problem.

This brings up another question -- is Uronema susceptible to treatment with metronidazole? I have looked for this information but I have not been able to find it.

thanks again.

 

[pescadero]

<a href=showthread.php?s=&postid=12204665#post12204665 target=_blank>Originally posted</a> by JHemdal
You got to hand it to Ed Noga, he tries to cover all bases: "...hyperactivity, and lethargy..." as signs of Uronema! Both? At the same time? Or does the fish alternate?

yes, he's certainly got the bases covered. :lol:

i think he's right, though he's not especially clear. what i have observed is a biphasic change in the chromis' activity level. hyperactive, darting about in the beginning, followed by lethargy in the late stages of the disease. the lethargic stage begins with the fish in a nose-up posture at the top of the tank gasping for air with a high respiratory rate. this is probably a sign of an overwhelming infestation in the gill tissue that renders the gills ineffective at gas exchange. the lethargic phase typically ends with a tachypneic fish lying on its side on the bottom of the tank.

i understand the problem of papers that transiently surface on the desk and then resubmerge. if you could keep me in mind when it eventually surfaces, i'd greatly appreciate it.