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black tail disease in rainbow trout
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Author:  hydrophilia [ Dec 9th, '09, 13:34 ]
Post subject:  black tail disease in rainbow trout
Well, finally, after envying all the fish and other good stuff you Aussies have, I've got something you Aussies can't get: whirling disease! AKA "black tail disease", it affects trout & salmon. This disease has spread over much of the world, but not "down under". In this case, it has affected one of the thirteen trout I put into my indoor aquarium. I don't know about the 25ish in the pool or the 70ish in the big greenhouse system. I am NOT happy.

I had noticed the little guy sitting off alone and not gaining nearly as well as the others (well, the other 11 live ones as one jumped out and was discovered dried behind a cushion.) Looking at him closely a couple days ago I noticed his tail was markedly darker, nearly black, and googled "'black tail disease": whirling disease. Fortunately, the infection should not increase (as the life cycle requires tubifex worms after they absorb the spores from a dead and decaying fish), but I do not know how many have little ticking time bombs inside them. I'm also going to inspect the fish as I transfer them from the blue barrel into the big tank and destroy any with signs of problems. :( Well, at least the cat will be happy.

If anyone has any other ideas I'm open for suggestions. At least the catfish will not be affected.
Author:  KudaPucat [ Dec 9th, '09, 13:46 ]
Post subject:  Re: black tail disease in rainbow trout
My condolences :-( not a good thing.
there is no treatment?
Dogs love trout too. My cats get too freaked out that their food is looking at them.
quarantine is a good idea.
worm treatment in their food wont help? You can egt an 'all wormer' don't know if it fixes tubifex. You add the tablet to a jar of water dissolve it, then add bloodworms for 20 mins or so. the trout will snap up blood worms.

What I'm saying is make sure this is not a problem only for large scale aquaculture and wild populations. You may be able to save the little fellas.
Author:  chillidude [ Dec 9th, '09, 13:47 ]
Post subject:  Re: black tail disease in rainbow trout
hydrophilia wrote:
Well, finally, after envying all the fish and other good stuff you Aussies have, I've got something you Aussies can't get: whirling disease! AKA "black tail disease", it affects trout & salmon. This disease has spread over much of the world, but not "down under".


Congratulations Hydro - you must be very proud :roll:

On a more serious note - that sucks. Is there a cure ?

Never heard of it before.
Author:  Troutman [ Dec 9th, '09, 21:27 ]
Post subject:  Re: black tail disease in rainbow trout
hydrophilia wrote:
but I do not know how many have little ticking time bombs inside them.


According to one of my books it takes 40 - 60 days for the fish to show symptoms. Is the the fish with the black tail swimming round in circles chasing its tail yet?? The bad news is that there is apparently no treatment.
Author:  hydrophilia [ Dec 9th, '09, 23:29 ]
Post subject:  Re: black tail disease in rainbow trout
Thanks for the condolences. The one with the black tail went to meet it's maker a few minutes after diagnosis, but it disappeared in the half-hour before I went to retrieve it for the cat, so someone got it.

There is no cure for infected fish, but at low levels it may not give problems. Rainbow trout are one of the most sensitive, so only a few parasites can damage them badly.

Apparently, they are almost entirely invulnerable once the cartilage has ossified by 5 months old, so I may have a very light infection that will only affect a few fish and go no further. *crosses fingers*

Other that this little joy and the difficulty of keeping O2 levels high (just bought a new air pump that should arrive soon), trout are great: they grow fast, enjoy cold water, and eat enthusiastically.
Author:  goola [ Dec 9th, '09, 23:49 ]
Post subject:  Re: black tail disease in rainbow trout
One of the larger trout farms here got infected with whirling and they had to cull and sanitize (bleach) everything to get rid of it. It not easy to get rid of and lingers in the tank crevices. Good luck.
Author:  Angie [ Dec 10th, '09, 05:50 ]
Post subject:  Re: black tail disease in rainbow trout
Whirling disease does take a host (tubifex worms) to infect fish. However, external signs alone are not adequate for diagnosis as it can mimic BCWD and IHN so you may want to have it checked. Some colleges and some extension agencies will do it for free or for a nominal fee- you may want to check into that for confirmation.
If you find that it is whirling disease, you should destroy all the fish (before stocking new) as infected mature fish do not display the tail chasing and you do need complete disinfection of your facilites and equipment and allow to stand for 4 weeks and repeat disinfection. All the water will have to go as well as this is a protozoan parasite and it is the worms which releases the spores and they could have been transported with the incoming water or even the slime coating on the fish. You may be able to get away with UV lighting but it would have to be strong enough to treat your system. Also make sure that you can't contaminate any bodies of water as this will spread in open waterways.
Author:  KudaPucat [ Dec 10th, '09, 06:53 ]
Post subject:  Re: black tail disease in rainbow trout
Ick, sounds really nasty :-(
Author:  hydrophilia [ Dec 10th, '09, 11:12 ]
Post subject:  Re: black tail disease in rainbow trout
Angie,

Thanks for good info. UV filter might be interesting possibility as needed.

None of the symptoms match BCWD or IHN, so I think I am clear there.

It would be the height of irresponsibility to allow water or fish into local streams and would harm our goal of making it easier for us to keep fish, so I'll make sure to cook or burn all trout heads/bones/fins before letting them leave my control since the spores settle in the cartilage. I will not worry about burying the guts raw as they should be spore free. *sigh*, I forgot about all that for a moment; what a pain!

Might sterilization be going overboard since I am not a breeder and this is clearly a light infection? Although there are some reports of spores being shed from live fish, most folks say they only are shed from dead fish (rotting or being digested), so good tank hygiene should help there. One life stage requires tubifex worms (a breeder control measure is to keep young fish out of earthen ponds), so good solids removal and a few goldfish or catfish to eat the worms or flush them into growbeds over the troutless summer should deal with any infections in my system (I hope).

I am more concerned about the fact that I am getting infected fish: I guess this is a symptom of too much required paperwork: people stay out of the light and infections can spread. Reminds me of my business: someone calculated that it costs around $7,000 per year to deal with the legalities of having an employee (not including required payments and taxes), so many folks just pay cash. If keeping fish were easily legal, perhaps with an online open-book test to give us a little knowledge, folks would be informed and would probably quickly report any infections.

Oh, well.
Author:  Angie [ Dec 11th, '09, 03:30 ]
Post subject:  Re: black tail disease in rainbow trout
I feel for you, this must be a frustrating time. Having delt with pretty much every disease and catastrophe that can occur raising aquarium fish, I understand. You can try not sterlilizing your system but we are talking about water-born spores- think small like mushroom or mold spores- they can hide anywhere. It sounds like you would have an on-going problem unless you use UV before reaching the fish tank(s). Fortunately this disease is a fish illness and won't affect your plants so the choice is ultimately yours. If you choose this route, just remember to have dedicated equipment- one for plants, one for fish and practice good personal hygene (hands, clothes) or you run the risk of cross-contamination.

Do you mind me asking who your trout supplier was? I also live in California and I don't want to buy from a contaminated source. This disease is considered so bad that if you have contaminated earthen ponds, it is suggested to concrete them instead.

Also, too, have you ruled out that the orginal contamination didn't come from your water source? That is also a possibility.
Author:  gemmell [ Dec 11th, '09, 13:27 ]
Post subject:  Re: black tail disease in rainbow trout
Massive props to Australias quarantine. We're the only country in the world without varroa destructor (which is killing all the bees) and we don't have this either. Most countries I have travelled to have a lot of security and very little quarantine, where as we seem to be just the opposite. One pro to being a big island.
Author:  hydrophilia [ Dec 11th, '09, 14:13 ]
Post subject:  Re: black tail disease in rainbow trout
Angie wrote:
I feel for you, this must be a frustrating time. Having delt with pretty much every disease and catastrophe that can occur raising aquarium fish, I understand. You can try not sterlilizing your system but we are talking about water-born spores- think small like mushroom or mold spores- they can hide anywhere. It sounds like you would have an on-going problem unless you use UV before reaching the fish tank(s).

As far as I understand it, the fish are only infected up to five months of age and I figure I am at that point in November. I also understand that intensity of the infection is very important and that a lot of hatcheries have given up on complete eradication, trying instead to simply keep infection severity low enough that there is no whirling and little blacktail and calling that good enough. I don't think that my system will infect future fish and surely not at problematic levels.

The only bright spot of this disease in a recirculating system is that, unlike most diseases, there should not be any fish-to-fish infection. The crowding should help disrupt any tubifex worms and stop that part of the life cycle as well.

Angie wrote:
Fortunately this disease is a fish illness and won't affect your plants so the choice is ultimately yours. If you choose this route, just remember to have dedicated equipment- one for plants, one for fish and practice good personal hygene (hands, clothes) or you run the risk of cross-contamination.

Do you mind me asking who your trout supplier was? I also live in California and I don't want to buy from a contaminated source. This disease is considered so bad that if you have contaminated earthen ponds, it is suggested to concrete them instead.

Also, too, have you ruled out that the orginal contamination didn't come from your water source? That is also a possibility.


I'll make sure to keep my equipment out of any trout waters.
Our water is from a well, so no chance of infection there.
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