Help needed with a diagnosis.

[whitearmy61]

Back in August last year I introduced something into my tank and lost a number of Tangs to what looked like Velvet and now having introduced new fish a couple of weeks ago one is showing the same symptoms.

Everything I have read about Velvet suggests that it's a quick killer but with the deaths last year there was around 8-10 weeks between first signs of symptoms and first deaths, when they came I'd say I lost all of the fish in a two week period.

It is very difficult to get a clear photo of the fish but it's appearance is of a fish suffering from Velvet.

Can anyone think of what this might be as I can't see how a fish can go 8-10 weeks with signs of disease before death?

For what it's worth I have tried running NT labs anti bacterial in the dt which doesn't seem to have been effective and I have UV running. I can set up a qt tank but not big enough to house all of my fish for a fallow period and If at all possible would like to treat in the dt so I can erradicate whatever this is. The dt is 8x4x2 so catching fish is difficult without a major stripdown.

Many thanks in advance.

[ThRoewer]

Acquired immunity can protect fish for a good while against velvet. Few fish will be fully protected though. Most will have a light contained gill infection. Any adverse event that weakens the fish's immune system can trigger an outbreak. This can be starting rather slowly until the fish's immune system is weakened enough so it can no longer contain the parasite.
There are also indications that in an outbreak scenario immune fish need some none immune fish as "sacrificial hosts" to stay disease free themselves. Once those have perished the next weakest so far immune fish will get sick himself and so on. This would explain the one by one losses in short order.

If your tank is a FOWLR you can dose it with Chloroquine Phosphate. Otherwise you will have to catch the fish and treat them in a separate HT (recommended procedure even with a FOWLR) and leave the DT fallow for 6 to 8 weeks.

[Sk8r]

velvet/oodinium is parasitic, not bacterial. I would suspect due to the lingering nature of it that it was indeed some sort of bacterial infection. Because symptoms overlap and there are no photos, I suggest searching 'vibrio,' 'pseudomonas,' mycobacterium', 'and aeromonas', etc, and seeing if any of these (pix online) look like the problem.

In treating with antibiotics, there are 3 types of med: gram negative, gram positive, and broad spectrum...the latter of which covers both types but may not be as specifically effective.

When faced with an erosive disease in freshwater I have had success with furan. But you may want to look up those terms and those diseases and see if anything fits the situation. THe length of time, to me, speaks of bacterial infection and possible an environmental stressor.

[Sk8r]

:) Well, you've got two routes to go, and I fully concur with THRoewer, you can have a lingering situation. If that IS the case, I'd take a close look at tank conditions, fish numbers re resources and room.

[ThRoewer]

Here you find some links to articles about the topic:
http://www.reefcentral.com/forums/showpost.php?p=24180522&postcount=5

This may also be of interest:

Studies on Amyloodinium ocellatum (Dinoflagellata) in Mississippi Sound: natural and experimental hosts (http://aquila.usm.edu/cgi/viewcontent.cgi?article=1125&context=gcr)

[whitearmy61]

Thanks for the replies.

Have looked at the bacterial suggestions I can't say the syptoms presented look anything like those so maybe it is a case of acquired immunity with velvet.

I think really I have no choice other than removing all of the fish and treating and leaving the dt fallow to stand a good chance of erradicating the issue.

Thanks again.