Glowlight Tetras... Whirling Disease?--Updated

[Channti]

Alright, The tank is well established. water stats are all exactly where they should be. Most frequent water changes were a 50% on the 9th, and a 25% yesterday.

Tank is 15 gallons, AquaClear 30, heated to 78F.

Residents are: 12 glowlight tetras (6 have been in the tank for about 8 months, 6 were added on saturday. The new tetras all appear to be healthy; identifiable because they're much smaller than my older tetras), Tank also has 3 otocinclus and 9 corydoras.

The only tetras so far effected have been from the "older group" of tetras I had in the tank.

Tank receives regular weekly water changes, of at least one 50% water change, occasional additional 25% water changes.

Symptoms of sick fish: Swimming on it's side, swimming in spirals.

First tetra who exhibited these symptoms died two weeks ago after being separated from the rest of the tank. I assumed it was a swim bladder issue.
Second tetra exhibited the same symptoms, I euthanized it via clove oil/Vodka on Sunday. This morning I have a third fish who is exhibiting the symptoms.

Google is telling me that this is "Whirling disease" which is something I've never heard of or seen in my 5 years of keeping tetras.

At the time of the first fish exhibiting the symptoms, there had been NO new additions to the tank (as far as fish, equipment or decor goes) for four months. When the fish start to exhibit symptoms, it progresses very quickly from just occasional side-swimming to swimming almost completely on their side, upside down, and then to nose up/tail up swimming...

Is there something I can do to treat the tank? Where did this come from? Will this affect the corydoras or otos?


EDIT: Fish are fed a Tetramin? flake... I think thats the brand. I buy it in bulk for my tank at home and bring it in a zip loc bag to school for these guys. They also get Aquarian Shrimp Pellets (once a week) and Wardley Alage Tabs (once a week).


UPDATE as of March 24th:

No more fish have shown the symptoms of this disease. Still unsure of what caused it exactly and/or how it entered the tank so suddenly. Final losses number was 3 glowlight tetras within 3 weeks. Beyond larger-than-normal water changes, I did nothing more out of the ordinary... I hate the feeling of helplessness that came with this disease, and I hope I never encounter it again.

 

[alihar]

I researched whirling disease a few weeks back as one of my rainbowfish was spiralling.
I read that it is very rare in the home aquarium and mostly affects salmanoids.
I believe it is spread by tubifex worms.
I had been feeding tubifex at the time but the fish is fine and has since had no episodes.
In my paranoia the tubifex went straight in the bin!
I never got to the bottom of why the fish was doing it so will be interesting to see other responses.

 

[afremont]

I researched whirling disease a few weeks back as one of my rainbowfish was spiralling.
I read that it is very rare in the home aquarium and mostly affects salmanoids.
I believe it is spread by tubifex worms.
I had been feeding tubifex at the time but the fish is fine and has since had no episodes.
In my paranoia the tubifex went straight in the bin!
I never got to the bottom of why the fish was doing it so will be interesting to see other responses.

I have read that "whirling" or swimming in a corkscrew style can be caused by a bacterial infection that has worked its way into the brain. Problems that affect fish single file are confusing as I expect parasites or other illnesses to spread out exponentially, not attack one fish at a time like some kind of predator.

Can't say that I blame you for tossing the tubifex worms, they're certainly capable of spreading things you don't want spread in your tank. I guess dried worms should be ok. I got my own internal parasite (nematodes) problems with some rescue fish I have, and I have no idea where they came from. I have some wild caught mosquito fish in a tank and I'm thinking they might have some part in all this.