Hi all. I made the fatal mistake of adding an unquarantined fish into my display tank. I've experienced a velvet wipeout with the exception of an orange back wrasse, orange head fairy wrasse, blue head wrasse, a file fish, 3 fire fish and 1 flame hawkfish. I noticed 2 of the wrasses got a mild case of it only after the rest of the tank was wiped out but now show no signs of it. The rest of the above fish mentioned never showed any visible signs. I've read that these types of fish can build an immunity to parasites for around six months. Wouldn't that eventually starve of the parasites since they are unable to feed on the immune fish. Meaning I would eventually be able to add new fish even though the tank has not run fallow. Not sure what people mean when say they are still carriers if they are immune to it. I am also installing a UV to try to make some of the parasites unable to reproduce along with weekly water changes to further dilute the water column of free swimmers.
Velvet Wipeout
- Thread starter Matt Whittle
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Hydrored
2500 Club Member
Unfortunately, the only way to guarantee is to run fallow.
Fishyfish22
Well-Known Member
Velvets in your system. Wrasses have a bit of protection because of the thick slime coat but whatever new fish you'll add will be exposed.
Only way is to remove the fish, put then through qt either through copper or ttm and let the tank run fallow for 30+ days. Check out the marine and disease stickies, or humble.fish for more info.
And always qt in the future.
Only way is to remove the fish, put then through qt either through copper or ttm and let the tank run fallow for 30+ days. Check out the marine and disease stickies, or humble.fish for more info.
And always qt in the future.
Corgigirl
Well-Known Member
I had something similar happen to me - I only had 6 fish, lost 5 of them. A pennant wrasse survived, never showed any signs. I agree with the others that the ideal is to quarantine the survivors and go fallow. On the other hand, I couldn't catch my wrasse without major disruption to my tank, so I went with your theory. I assumed the wrasse had immunity since he remained healthy. I left him in the tank and waited 80 days or so, adding in a UV sterilizer as well. Then I went to PetSmart and picked up a black molly. Three weeks later, she and the wrasse were both fine, no sign of velvet, so just a week ago I added two captive bred mandarin and a blenny (I had previously stocked pods, they had a great time multiplying in an essentially empty tank 
). So far, so good.
I'm not sure if I just got lucky, I think most here would say that's the case and I can't disagree. You have quite a few fish, I only had the one, so your mileage may vary. If the molly had succumbed, I was ready to tear down the rock work to catch the wrasse. I will stock slowly from here, quarantining all as I go. I'll let you know how that goes, I have a tang expected to day who will spend his time in QT. I'm thinking if he doesn't get it, I should be pretty safe. Keep your fingers crossed for me!
). So far, so good. I'm not sure if I just got lucky, I think most here would say that's the case and I can't disagree. You have quite a few fish, I only had the one, so your mileage may vary. If the molly had succumbed, I was ready to tear down the rock work to catch the wrasse. I will stock slowly from here, quarantining all as I go. I'll let you know how that goes, I have a tang expected to day who will spend his time in QT. I'm thinking if he doesn't get it, I should be pretty safe. Keep your fingers crossed for me!
Corgigirl
Well-Known Member
I'm not sure that's true...what you're describing is resistance, not immunity. Before I went this route, I did a fair amount of research. There are several articles out there that say if a fish is exposed to the parasite and recovers, that will impart at least a temporary immunity. Six months seemed to be the time I saw most. Those fish would still have trophonts attach, but they would drop off prematurely and not complete their life cycle, thus the parasite would die off. Here's one of the articles I found quickly, I would have to dig to find the others.
Cobb, Charles S., Michael G. Levy, & Edward J. Noga. 1998. "Development of Immunity by the Tomato Clownfish Amphiprion frenatus to the Dinoflagellate Parasite Amyloodinium ocellatum" Journal of Aquatic Animal Health, vol. 10 no. 3 pp. 259-263, 1998.
I am always interested to learn more though, if anyone has other articles regarding immunity, I would love to read them!
This is the logic I am using. If I waited months and the current fish are not getting infected so to speak because of their temporary immunity wouldn't the parasite be unable to feed and eventually die off? This coupled with the UV and water changes further diluting the free swimmers.
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hds4216
Valuable Member
Interesting, I was under the impression that the "immunity" we thought was just what you said, resistance. I read the article and it seems sound. I also found this one:
"Expression of infection-related immune response in European sea bass (Dicentrarchus labrax) during a natural outbreak from a unique dinoflagellate Amyloodinium ocellatum"
Omkar Byadgi, https://pubmed.ncbi.nlm.nih.gov/30266602/
Always good to learn something new! It does seem it may be genuine immunity.
