Some times it is the beginning signs of Ick. I will often treat for ick as soon as I see them scratching, since if I cannot see the ick yet most of it is probably in the free swimming stage, and that is the best time to kill it. Turn te heat up a little too. Ick doesn't like heat.

I would go with a parasitic issue as well. Clout is a good product.

Thanks for the tips-- I'll have to see what works with the crayfish too, as I've read that some treatments are toxic for invertebrates. Anyone used potassium permanganate? Today the fish are acting very oddly-- swimming up and down in one corner of the tank only... they will occasionally swim around to the other side, but mostly they are just clustered in that one corner... Never seen them behave like that! Is this also a parasite symptom? I have to treat them asap... just don't want to kill anyone in the process! Thanks again!

Potassium permanganate will make a real mess of your aquarium, first it will turn the water a pleasent purple color, but eventully it will turn yecky brown. I use NoxIch, Clout will probably kill the crayfish, as will anything with copper in it. Maracide by Mardell is probably the safest, but takes a bit longer to work. Don't forget to remove the filter carbon.

You could also set up a "hospital tank" with a box filter, pump, etc... just to treat the fish and not mess up the main tank (or crayfish).

The only problem with that is, if it is Ich, you won't bekilling it in the home aquarium. I realize it needs a host, but if its on the fish it is hard to kill, you need to kill the free swimming stage.

It's always a tradeoff and people have a philosophy of aproach. Mine is to treat the fish in a safe environment and not take chances with the main environment, particularly when dealing with "good bacteria". It's a choice!

Thanks for all the great advice! I have raised the temp and also did another water change and they have stopped flashing and itching for the past couple days. I still think I should treat them, as there is probably something still-- just maybe not as evident. Is that a bad idea though? I don't want to stress them unnecessarily...

I went to a LFS and they said to use "quick cure" (malachite green and formalin) at half the rate and leave the crayfish and plants. I bought the stuff and was going to use that, but decided to research more just to be on the safe side. Seems like formalin is the last thing I want to be adding to my tank. I think I will go with the suggestions for a malachite green-only treatments, (maracide or nox ich) which should not kill the crayfish in the process. I am thinking of just taking them out during the treatment also, as I don't think they are carriers or susceptible to ich. Anyone have experience with crayfish *ever* getting ich? I was just worried the parasite might be something other than ich, like worms or something, which the crayfish could have brought in... (maybe?!?) I've been trying to read as much as possible online since getting these guys---previously, I had only seen a crayfish once or twice in my life! And I also just discovered that my little "catfish" is actually a golden algae eater! Guess when he gets bigger he'll need yet another home...(sigh-- poor thing!) Anyway... Thanks again!!!! I really appreciate the help! :)

The crayfish won't get ich. When we used Formaldehyde at the wholesaler, I got the impression that it doubled as both a parasite and bacteria killer. The Malachite Green is like Methylene Blue and other dyes and all do the same thing. If it were me, and this is just a philosphical approach, I would set up a separate tank for the fish and kill the parasites there, not messing with the main tank.

Formalin does not remain in the water long, it disapates rapidly into the air, if you are running any type of air driven filter or airstone. If you don't believe me dose a tank and in a few minutes go over and take a breath near the top of the aquarium. You will smell the formalin as it disapates. I do like QUICK CURE, but Nox Ich works just as well, with out the formalin.

A hospital tank is fine for bacterial infections, but Ich will remain in the home aquarium. Even with bacterial infections, removing a fish and treating it does not remove the disease from the home aquarium.