Deadly, grey lint-like material tumbles and snags plants

[Don L.]

Hello.
I've had this freshwater 30G Community tank for over twenty years, but this is a new one on me! Appearing and multiplying quickly is this lint-like grey substance that tumbles with the water flow, and collects at leaf bases on mainly Java Fern plants. It is deathly toxic to Black Mollies, Variatus, and some Guppies. What is it, and more importantly, how do I get rid of it? so I can have all of my favorite fish again?
Note: It does not affect Neons, Corydoras or Black Skirt Tetras, and also wiped out every one of my Siamese Algae Eaters, very quickly. It has to be cured!

Thanks!
Don

[Scrup]

do you have any pictures? sounds like an outside contaminant...

[lowlight]

Pics would be a big help but I agree with aji1217, sounds like a foreign substance.

[VoidParadigm]

Without pictures we can't really help. Even if you could go onto google and find someone else's picture of it it would be much more help.

Doesn't sound like any algae I know of. In fact, although I doubt this is the answer, it sounds just like when a wad of cat hair from my long-hair fell into the tank the other day.

[Algenco]

the description sounds like the gunk that builds up in canister hoses, it isn't toxic though

[annageckos]

Are you sure it is algea? I have never heard of algea killing fish. Any photos? When did this start? Any info you can give us would be helpful.

Attack of the killer algea!!!!!!! Run!!!!!:14:
Sorry, that was the first thing that I though of reading the post. I watch way to many bad horror movies.:14:

[Crispy]

Do you have a pleco? could be pleco waste?

[Scrup]

Yeah cat hair is the first thing I thought of as well.

Perhaps the substance is only lethal when it is attached to claws?

[Don L.]

I did try and photograph the grey lint-ish material, but I can not get it to show up against the natural riverstone in the tank. I took a sample to a local fish expert, and he said it was dead brown algae that came loose from the gravel, and was decomposing, but obviously releasing deadly toxins into the tank too. I have suctioned it out about every other day, have done major water changes too, and the last Variatus has "come back to life", so I think that did the trick!
I will wait a good while until trying those susceptible species again (Mollies, etc).

[Wild Turkey]

The only thing I can think of that it could be an be toxic would be cyano bacteria, but ive never seen it in grey, only green/blue/purple

Brown algae is not toxic, and ime it wont turn pale like algae does when it dies. Thats because brown algae is made of small organisms, not actually algae.



I agree with above its probably just some build-up or fungus growing on some junk. Is the tank new or anything new in the tank? New tanks grow a lot of fungus ime, especially on wood or that kind of stuff. Its sometimes also hard to photograph.

If it is brown algae or fungus, its not what killed the other fish.


"tumbles in the water flow" and "hard to photograph" sounds like fungus to me.

[lowlight]

So what was it?