Tang has dark spots all over its body - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 21 Old 07-27-2010, 05:19 AM Thread Starter
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Tang has dark spots all over its body


In the past day or so our blond hair naso tang has developed dark spots all over its body. It's also had light splotches where it should be uniform gray for a while now, but I assumed they were just the result of scratches it got swimming against the live rock. I wonder if that was not the case after all and the splotches were indicative of something gestating inside it?



Does anyone have any idea what this is and what we can do to get rid of it?
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post #2 of 21 Old 07-27-2010, 06:17 AM
I found this

Typically a "disease" that is most commonly associated with Tangs and Surgeonfishes, but one that can be contracted by other species as well, what is referred to as Black Spot Disease, Tang Disease or Black Ich is actually caused by an infestation of tiny Genus Paravortex member turbellarian flatworms.
Although parasitic organisms that are much less dangerous and life-threatening, as well as rather easy to get rid of compared to other ich diseases such as Oodinium, Cryptocaryon, and Brooklynella, nonetheless it is a problem that needs to be treated upon recognition to eradicate infected fishes of these parasites.

The Life Cycle of These Worms
  • Living in the substrate until mature, an adult worm seeks out a host fish.
  • After feeding for about six days, it falls off into the substrate.
  • About five days later the worm's body ruptures and releases a new population of young worms, and the cycle starts again, but in larger numbers.
Symptoms to Look For

Once these worms start feeding on a host fish they acquire pigmentation, which causes the appearance of black spots about the size of a grain of salt on the body and fin membranes. Worms that freely move about on fish, the spots do not always remain stationary. On light colored fish they are easy to see, whereas on dark colored ones they may go unnoticed at first. Fish will scratch up against objects in an attempt to dislodge the parasites, and if allowed to progress the fish become lethargic, loss of appetite and colors occur, rapid respiration develops, and secondary bacterial infections can invade damaged tissue sites.

Treatment Recommendation
Give all infected fish a freshwater dip, followed by a formalin bath and continue treatment in a QT.

Preventing Reinfestation
Reinfection will occur no matter how effectively the fish have been treated if these parasitic tubellarian worms are not eradicated from the main aquarium. Unfortunately because they can survive for several months without a host, this is often not an easy thing to do, but here are some suggestions.
  • Leave the main aquarium devoid of all fish for several months.
  • Young worms live in the substrate and feed on detritus and organic debris until such time they mature and go in search of a fish host. By siphoning up excess organic matter that can build up on the bottom of the aquarium can help to control their numbers.
  • For fish-only tanks that have no freshwater sensitive invertebrates present, hyposalinity can be applied.
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4x1.5x1.5 planted tetras,harlequins,
otto,WMM,2 types of celebes rainbows,rcs,amano, bamboo,red ramhorns,MTS
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post #3 of 21 Old 07-27-2010, 07:09 AM Thread Starter
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Thanks, kitten penang. It seems my aquarium is having a stroke of bad luck lately.

I gave the tang a freshwater dip last night. I suppose I should try to give all of the fish a freshwater dip this morning before work. I doubt I'll be able to catch the gold head sleeper goby, though.

As far as treatment, I can't leave the main aquarium devoid of fish because it's our only aquarium. As far as I know, we've already been applying hyposalinity somewhat with a specific gravity of 1.018. Should the specific gravity be lowered further? If so, to what?

Is there anything else I can do to help get rid of this? Are there any reef safe medications that may help?
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post #4 of 21 Old 07-27-2010, 10:10 AM
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i would not dip the other fish in the tank, only the tang who is showing signs of infection. i would also ride it out without medication. if you can get this guy eating more, and adding garlic and selcon to its food, it has a better chance.
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post #5 of 21 Old 07-27-2010, 02:19 PM Thread Starter
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I already dipped the rest of the fish in the tank, except for the gold head sleeper goby who I could not catch, this morning before work. I noticed something appearing to protrude through our passer angel's side, and the fish looked like it was trying to scratch itself on the live rock.

As for riding this out without medication, I spent all morning reading corroborations of what kitten penang posted, that the worms will mature, fall off, and release over 100 larvae each that will attack the fish unless/until the tank is either treated or has no fish in it for 4 - 8 weeks so that the parasites have nothing to feed on. http://books.google.com/books?id=SAd...page&q&f=false

I found a product called Prazi Pro that is supposed to kill such parasites without harming live rock, crabs, etc. and was planning to pick some up after work to use on the tank tonight. You would not use it despite the appearance of the tang and the nature of paravortex?
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post #6 of 21 Old 07-27-2010, 07:15 PM
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i did not know after they died larvae was produced, in that case treatment sounds needed. remember though for future issues its sometimes more stressful on a fish to use a chemical, then to let the fish fight off the disease on its own. sadly this fish hasnt been eating well enough for its immune system to be up to par, and im sure thats contributing a good deal to the issue. i would still feed garlic and selcon soaked foods to your fish, maybe even a live blackworm or roe treat.
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post #7 of 21 Old 07-28-2010, 07:32 AM Thread Starter
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Thanks, Jon. Coincidentally, the tang has been easting like a champion since I noticed the paravortex on him.

Anyhow, I went to the LFS yesterday and bought Prazi Pro. The directions said to administer it after as large a water change as possible, which was good because it coincided with the last of my 50% water changes to bring my nitrates down.

I turned off my skimmer as per the instructions and added 3 teaspoons to my 55 gallon tank. Hopefully I'll have good news to report within a few days...
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post #8 of 21 Old 07-28-2010, 10:00 AM
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Originally Posted by Administrator View Post
Hopefully I'll have good news to report within a few days...
I hope you do too. Good luck with him, he's a beautiful fish.

If you don't stand up for something you'll fall for anything...
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post #9 of 21 Old 07-29-2010, 06:10 AM Thread Starter
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Thanks, Kym. I'd hoped to wake up today and find him doing much better, but instead it looks like there are many more black spots and he's doing considerably worse.



I gave him another long freshwater dip this morning, but I don't expect much to come of it since his previous freshwater dip apparently had no effect.

The PraziPro directions say "a single treatment lasting 5 - 7 days is normally sufficient. Retreat as necessary, but no more than once every three days" so it looks like I have to wait until Saturday to dose the tank again since I just dosed yesterday. I hope he makes it that long.
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post #10 of 21 Old 07-29-2010, 11:26 AM
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Prolonged immersion in praziquantel can have negative effects on fish. I would have to check some references but usually I treat with 3 hour baths every 5 days for a total of 3 dips. I think I dose at 36mg prazi per gallon...again I would have to check since I have the drug compounded. I agree with kitten penang and onefish2fish....it appears to be Tang Turbellarian Disease and only treat those individuals affected. Repeating freshwater dips this soon may cause too much stress which leads to worsening of the condition.

Last edited by drvet2002; 07-29-2010 at 11:34 AM. Reason: additional thoughts
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