Strange Sickness

[net_shark512]

I have a problem. My 20 gallon has been set up for more than 3 years never had a problem with it. I have something that looks like ick but I don't think it is. It shows up on only certain fish. It has killed my 2year old clown loach, 2 gold fish and a neon. there are 4 fancy guppies in there that never got it and a small cory cat. I use maracid that usually works well. I thought I got rid of it.Yesterday I brought home a chinese algae eater and now he looks like he is getting it. My question is if its ick why doesn't the guppies or the cory cat ever get it? I am most upset over the lose of my clown loach. I never seen anything like this. I know the gold fish don't belong in a heated tank they were fish we won at the fair and my wife put them in there they did fine for a long time.(just wanted to say that so I don't get flamed for mixing cold water fish with tropical) If anyone knows whats going on please help me! thanx,
Bob

[wetmanNY]

Some fish are more resistant to attacks of the ciliate parasite Ichthyophthirius multifiliis, and now Cornell researchers are investigating what fishkeepers have noticed: that once they've recovered from an infestation, former hosts of the parasite gain a level of resistance to it.

Your reinfestations come from putting new fish with subclinical infestations directly in with the others, without a separate quarantine.

I've just been battling Ich in my Q Tank: two Spotted Headstanders and a German Ram succumbed to the parasite and the medication (Maracide) I used. Three other Rams are fine. Not a very successful quarantine group-- but imagine if I'd put these newcomers right into a big planted aquarium.

[net_shark512]

What really bothered me was the medicine (maracide) wasn't killing it the fish just got worst and died. the other fish were fine. I did the 5 day dose. So I don't know if I ever really killed it or just brought more home with the new fish.
Bob

[wetmanNY]

In quarantine, if fish get sick and are successfully medicated, you set back the clock to zero and begin the quarantine all over again.

If I hadn't rushed and doubled up fishes from two different sources in one quarantine, I'd never have had to put these Rams through the trial...