Do fish develop Immunity to Ick?

[Ziggs180]

Was going to put this in the Unhealthy fish forum, but I don't really need help, and i'll explain now.

Last saturday I bought 2 Platies and the most awesome looking swordtail ever. However after my fish were bagged, I saw in the corner of the platy tank a very sick ick infested platy. I decided to buy my fish anyways, and just up the heat. Well, my Heater wasn't working properly, and my Temperature never went above 82 Degrees, and I was to busy with school these past couple of days to notice. when I looked at my tank, I noticed that all of my new Fish had Ick! however none of my old fish, who had been through a Ick infestation before, were completely healthy.

I fixed my Heater, and the Temperature was raised to about 86 Degrees, two days ago. Yet today, when I woke up, there was absolutely no signs of ick anywhere in my tank. I was expecting my old fish to start showing signs of Ick, but, nothing. now then new fish are swimming around socializing, and pigging out on food.

Has anybody had this happen to them?

 

[Alkane]

Your new fish were exposed to the freeswimming parasite. It takes around a week or 2 depending on the temp for ich to go through its life cycle. So your old fish never got exposed to the infectious stage of the parasite

I have heard of fish being immune to iCh but haven't read any proof.

 

[KaylNeko]

+1 on your new fish being exposed to the free swimming parasite. Leave the temperature up for at least another week if you don't see any more white spots (I'm sure you know that ).

What fish can do is develop a resistance to a minor infestation. This is partially where the "ich stays dormant in the tank" myth comes from (the other origin is people not completing a full course of treatment). A very minor case of ich can be asymptomatic in fish until something triggers a stress reaction that makes them vulnerable. This is actually why some QT procedures recommend putting one of your existing fish in with the QT fish and doing something to stress the new fish out (ie, dropping the tank temperature for a day or so then bringing it back up. Going for mild but enough to trigger a mildly reduced immune system). The first ensures that your existing fish don't have a disease that they have become resistant to that the new fish will be affected by when exposed, and the second ensures that no one has anything that a stress reaction will bring into full fruition that can affect your tank.

 

[Ziggs180]

Well I guess that makes sense, but why is that the white spots are mostly gone (just looked at the swordtail, and saw his tail still had a few spots) after 2 days of 86+ degrees.

 

[Alkane]

Ichthyophthirius multifiliis, ich, ick, fish white-spot disease: facts, life cycle, pathogenicity, bibliography at MetaPathogen

This may help understand the cycle.


Heat speeds up the cycle, it doesn't actually kill the parasites.

 

[BBradbury]

Was going to put this in the Unhealthy fish forum, but I don't really need help, and i'll explain now.

Last saturday I bought 2 Platies and the most awesome looking swordtail ever. However after my fish were bagged, I saw in the corner of the platy tank a very sick ick infested platy. I decided to buy my fish anyways, and just up the heat. Well, my Heater wasn't working properly, and my Temperature never went above 82 Degrees, and I was to busy with school these past couple of days to notice. when I looked at my tank, I noticed that all of my new Fish had Ick! however none of my old fish, who had been through a Ick infestation before, were completely healthy.

I fixed my Heater, and the Temperature was raised to about 86 Degrees, two days ago. Yet today, when I woke up, there was absolutely no signs of ick anywhere in my tank. I was expecting my old fish to start showing signs of Ick, but, nothing. now then new fish are swimming around socializing, and pigging out on food.

Has anybody had this happen to them?

Hello Z...

The "Ich" parasites have to be present in the tank to cause an outbreak and some fish can carry the parasite without having the disease. Healthy fish with strong immune systems in a well maintained tank aren't likely to be bothered by parasites. If you are what I call a "water change slacker", pollutants will build up in your tank and stress your fish. Stress will affect the fishes' immune system and the "Ich" parasite can infect them.

I remove and replace at least half the water in my tanks weekly and use a teaspoon of standard aquarium salt in every 5 gallons of my replacement water. Most fish pathogens are unable to tolerate even a trace of dissolved salt in the water. I've used salt for several years in my tanks that include several species of salt sensative fish and have never had a problem.

The key to a healthy tank is to keep the water stable through large, weekly water changes and know the source for your fish and plants very well.

B

 

[KaylNeko]

The spots disappeared because the 82* heat sped up their life cycle so that they fell off the fish to reproduce. The 86* will cause them to not be able to reproduce, but ensure you keep the heat up until a week after the last spot seen just to catch any that might have hidden in the gills of the fish. I do 2 weeks period just to be sure.