Skinny Gastro's

[Gary Herring]

I probably should have updated this thread before, but anyway.....

Unfortunately, dispite my best efforts at treatment, 4 ouy of my 5 Gastro's got skinny (as above) and died 1 by 1 - the last one just over a week ago. The Levimasole (kindly supplied by Graeme) did'nt make any difference either positive or negative, so internal parasites were ruled out as the cause - leaving presumably only internal bacteria. I did isolate them and tried with an anti-bacterial and loads of water changes, but to no avail. No other fish were affected, hillstream or otherwise, and the 1 gastro that was'nt is thriving. Wierd huh?

Possible causes? Not sure TBH, I was hoping one of you might be able to help me on that. But as I was saying to Emma the other day, I have got one hunch - farmed algae rocks (which is why I should have posted this earlier). I remember Martin linking something about bio-films a while ago, and its the only thing I can think of as a possible cause.

Any suggestions welcome!

[Graeme Robson]

Impossible to know that Biofilms is the cause unless access to a laboratory is at hand?

Biofilms Grows just about anywhere. All it takes is microorganisms, moisture, nutrients, surfaces.

[Gary Herring]

Another possibility is those *!@$%* snails. I used to squash em and leave em on the rock or glass for the hillstreams to find while grazing. I've since found out though that they can harbour all sorts of nasties including bacteria. Strange how it was only the Gastro's affected though. Anyway, all is fine now - just one of those things I s'pose

[Jim Powers]

Yes, snails can spread disease. I put contaminated snails in a tank once and pretty much wiped out the loach population.

[mikev]

My 2c on levamisole:

While I think this is one of the very best drugs out there and a must-use drug for new fish, I doubt it could have been helpful in your situation.

Here is the thing: parasitic worms that levimisole takes out are generally large enough to quickly kill small fish. This goes both for direct worms (like nematodes) and the tape worms (which is the #1 cause of the Wasting Disease in loaches). A one-inch fish would not last very long in case of either infection and is likely to die faster than develop the "skinny" appearance, the worms are just too large to establish a balance.

So whatever killed your gastros is more likely to be bacterial|other small parasite in nature, and the bacteria may still be present in your tank; for example, the surviving gastro may be the carrier.

As for affecting only gastros: My recent incident with a sucker-killing bacterial infection affected three sucker species; but among the three, gastro had the least resistance, chenis were in the middle and beaufortias were the most resistant. It is not the same infection, most likely, but it is fully possible that the same problem would develop with other species, only taking longer.