Killer fog from Hell!

[wilkinss77]

Can anyone help? The water in my 2' x 12" planted tank has gone foggy like milk has been poured in. It's been a couple of weeks now. At first I thought a bacterial bloom & thought nothing of it. But this isn't harmless-the fish started gasping & some died. It got worse & I lost more fish. Tried an ammonia test with a new Colombo kit- zero.
I've tried:
A complete water change. It got worse.
Replacing the gravel bed, because I thought recent white spot treatment had killed Malayan burrowing snail & poisoned the gravel. Fog temporarily started to clear, but it's back & still killing fish.
What I'd like to know is what it is, what could have caused it & how to remedy it?
The fish are behaving like they're gradually being poisoned or have a gill disease.
At the same time the fog appeared, the tank became plagued by a slimy green film of algae, which my 2 bristlenose plecs won't touch- they usually keep the tank spotless.
I've also tried cleaning the filter sponges in aquarium water.
Temperature is 77-78f.
pH is 7.5.
Ammonia is zero.
This tank has been running successfully for more than 4 years.
I'll try to post a pic tomorrow. Looking really closely, the fog seems to consist of millions of tiny (pinpoint size) white globular particles that the internal filters don't pick up.
Anti flocculant clearing agents don't work either.
Can anyone please help?

 

[Andy Sager]

A couple of possibilities when you have fog in an old tank is a reaction to medication or a blue/green algae explosion.
Blue-green algae will suck the oxygen out of the water which kills the fish. A medication reaction can cause precipitates which can cause a fog but they don't usually kill the fish. Because you changed the substrate, you may have overkilled the bacteria bed and this is the typical " New Tank" fog. Without pictures, it's a tough call for exactly what happened. What I would suggest is to remove whatever fish you have to a bucket or two or a spare tank with new water ( nothing from the tank goes in these) ,do very large volume water changes until the fog is gone for 24 hours and get some polishing pads for your filter. If the fog continues after doing this, you may be better off just breaking down the tank and resetting it up. If the slimy algae is in fact blue-green algae, killing it is going to be tough as the best way to treat it is using erythromycin but that can also kill your nitrifying bacteria so you will basically be starting the tank over again. You also need to siphon out as much of it as possible which in the end, is more work than resetting the tank up after a thorough cleaning.

In the end, you really want to not use medications in your main tank and all treatments should be done in a separate hospital tank to help avoid medication related issues in the main tank.

 

[wilkinss77]

A couple of possibilities when you have fog in an old tank is a reaction to medication or a blue/green algae explosion.
Blue-green algae will suck the oxygen out of the water which kills the fish. A medication reaction can cause precipitates which can cause a fog but they don't usually kill the fish. Because you changed the substrate, you may have overkilled the bacteria bed and this is the typical " New Tank" fog. Without pictures, it's a tough call for exactly what happened. What I would suggest is to remove whatever fish you have to a bucket or two or a spare tank with new water ( nothing from the tank goes in these) ,do very large volume water changes until the fog is gone for 24 hours and get some polishing pads for your filter. If the fog continues after doing this, you may be better off just breaking down the tank and resetting it up. If the slimy algae is in fact blue-green algae, killing it is going to be tough as the best way to treat it is using erythromycin but that can also kill your nitrifying bacteria so you will basically be starting the tank over again. You also need to siphon out as much of it as possible which in the end, is more work than resetting the tank up after a thorough cleaning.

In the end, you really want to not use medications in your main tank and all treatments should be done in a separate hospital tank to help avoid medication related issues in the main tank.

Erythromycin is not available here in the UK for aquarium use.
The treatments I use are specifically for main tank use & have to be for protozoan parasites such as white spot (ich), flukes etc because the parasites are in the tank as well as on the fish.

 

[V227]

The mass of white particles that suddenly appear in a fish tank sometimes originate from the hot water heater. It's due to calcium build up.

Another cause could come directly from the water pipe, if your local water company has been working on the line.

 

[Andy Sager]

Erythromycin is not available here in the UK for aquarium use.
The treatments I use are specifically for main tank use & have to be for protozoan parasites such as white spot (ich), flukes etc because the parasites are in the tank as well as on the fish.

It will depend on what the ingredients are in what you are using. Case in point, most ( if not all) plants will not react well to the use of Malachite Green which is a common ingredient for fighting Ich.
Again, pictures will help.