Hemorrhagic Septicemia in a Yellow Tang

[pescadero]

I have a Yellow Tang that's developed red streaks that radiate outward along its dorsal fin. The streaks became more prominent, and were accompanied by an occasional red spot on the flanks, just forward (cephalad) of the caudal peduncle. The red streaks in the dorsal fin appeared to be getting worse, and looked suspicious for bacterial hemorrhagic septicemia.

I started treatment by prolonged immersion in a hospital tank with Erythromycin (40mg/gallon). 24 hours into the course of treatment, the petechial hemorrhages appear to be getting worse -- all of the fins and tail are now effected, and now the face is also starting to show signs of redness.

The tang's appetite is still good -- he's eating spirulina flakes, nori, and blanched vegetables (broccoli and spinach). He's eating the veggies like a pig.

I'd like to ask if anyone has treated this problem before (especially in a yellow tang) and if so, what treatment method did you use and what were your results. I know that 24 hours into treatment is too soon to expect reversal of the dermatologic signs, but their progression is not at all encouraging.

Water chemistry tests were impeccable prior to the onset of the problem. I think that the causal factor was a 5 degree temperature drop.

TIA.

 

[Percula9]

What caused the 5 degree drop? If you don't get improvement soon, maybe change to Furan2. The fact that he's still eating is a good sign.

 

[JHemdal]

Percula9,

I agree that pescadero should consider changing antibiotics. Erythromycin has little affect on external marine pathogenic bacteria, but it can be 100% inhibitory to biological filters in recently established aquariums.

pescadero,
Just to play it safe, you might test your tang's water for excessive ammonia now and for the next few weeks. The erythro might have nuked your bio-filter (unless of course you are maintaining water quality through some other means). There is a sticky on a thread about this problem with yellow tangs - I haven't read it all myself, but perhaps you might find some help in it:

http://reefcentral.com/forums/showthread.php?s=&threadid=138705

JHemdal

 

[pescadero]

thanks everyone for your input.

maintaining water quality should not be an issue, as i am monitoring NH4 / NO2 / NO3 daily and I am performing 10% water changes once of twice daily. so far so good...

WRT antibiotic selection, admittedly antibiotic selection can be hit or miss when you don't have culture results that accurately identify the pathogen and its antibiotic sensitivity. i have researched the topic to see what individiual organisms most commonly cause hemorrhagic bacteremia in yellow tangs, and believe it or not, I actually found a citation that recommended erythromycin. sine i had some on hand at midnight, that's what i started with. the good news is that we're 2.5 days into the course of treatment and the progression of the lesions has been arrested.

i'm still trying to get a better handle on this WRT antibiotic selection. could anyone identify three most common organisms that are likely to cause hemorragic bacteremia? information like that would help to facilitate rational antibiotic selection, rather than just choosing drugs based on anecdotal experience.

i know that one genus that causes the disease that i have not treated for is vibrio, and that eryc is not suitable treatment for that genus. a better choice would be a tetracycline or TMP/SMZ.

one thing that strikes me as odd about antibiotic recommendations for aquatic species is that they all tend to focus on antiquated drugs that are very cheap, but have long been otherwise abandoned.

 

[Percula9]

Its hemorrhagic septicemia, the organisms responsible are
Aeromonas spp, psuedomonas, and vibrio. There are other antibiotics like oxytet, and Romet but are only used in large aquaculture systems. Even their use is strictly regulated due to the fact that these are fish grown for human consumption. Since the lesions growth have ceased, hopefully he will recover.

 

[pescadero]

thank you. i had encountered a list somewhere that included aeromonas vibrio, and a species of pseudomonas that i think has now been renamed to something else. unfortunately, i could no longer find the link.

 

[pescadero]

At 3.5 days of antibiotics, the hemorrhages are no longer intensifying, in fact they seem to be ever so slightly more pale than they were yesterday. I'm inclined to think that I'm experiencing a positive result. Hopefully the signs will be clearer tomorrow.

I have a question though -- when antibiotic treatment is effective, how long does it need to be carried out, and how long does it take for the petechial hemorrhages to resolve? Do the hemorrhages normally resolve during the course of antibiotic therapy (ie: can their resolution be used to define the endpoint of treatment), or do the dermatologic manifestations take longer to resolve than the time that it takes for the infection to clear?

thanks.

 

[Percula9]

Treatment lasting 7-10 days should be sufficient with a maximum of 14days should clear the infection. Dermatologic appearance may take a ltlle longer to clear, but the two should be close. Your at 3.5days now, so another 7days of treatment should do it.

 

[pescadero]

I'm happy to report that on day 4.5, the infection seems to be clearing up. the YT seems to be displaying all of the signs of clinical defervescence, including improved appetite and most notably, marked diminution of the cutaneous lesions. the lesions on the face, flanks, and tail are all but resolved. the lesions on the dorsal and anal fins have regressed to 50% of their peak size, and there is significantly less congestion in the hemorrhagic areas that remain. (ie: they're pink now and not bright red).

it looks like the cutaneous signs will be resolving before the antibiotic regimen runs its full coure. of course, i'm still coing to continue treatment for full 10-14 days.

thanks everyone for your help. it looks like the Yellow Tang is turning the corner.

 

[Percula9]

Glad to hear things turned around for him. It's a good felling, congratulations.