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We have all heard it before, that a temp change (especially cooler) will cause Ich. But why?? <img src='/images/forums/confused.gif' border=0>

If i remember correctly (someone correct me if i'm wrong) the reason why water temperature changing causes ich, is the fact that it stresses the fish, thus causing them to be less resistant to contracting ich. Heidi

"I've got a great ambition to die of exhaustion rather than boredom." Thomas Carlyle

exactly Heidi. The ich organism is always present in your water, but when your fish is feeling 100% their immune systems are capable of fighting it off. Sudden stresses like a temp change will cause your fishes immune system to be compromised and their chance of falling ill to any of the various nasties living in the tank water is drastically increased.

So even the addition of new fish (who are not infected) can cause stress, thus reducing immunity to ich? Interesting. How 'bout just a water change? Are those stressful to fish even if you keep temp same? I often wonder if they are afraid and freaked out by gravel vac and moving things around in the tank.

Im sure all those things you listed could cause stress, it's the *amount* of stress they cause that's important tho. I don't think that a water change with same temp, de-chlored, equal PH water is going to depress their immune systems to the point where they fall ill, though. If anything, the good you are doing them by giving them clean water and removing toxins far outweighs the stress In my Opinion, anyways.

I don't believe that Ich is always present in aquariums. It can be completely eradicated.

Agree with Malaikah, Is not always there. I have tried a new treatment for ich, it has work wonderfully with cories, bettas, rams and tetras. One friend of ine gave me the "recipe" one of my bettas had ich and I gave it a chance, it removes the ich completely in 3-4 days, no effects in the bacteria the only effect is phosphates, but anyway you should do a water change after eny madication right so there should be no problem . I used Flagyl (Metronidzole) 250 mg for 10g of water, I used 4 times without cassualties. Of course is desireable to rise the temp about 30 Celcious, and i repeat it removes the parasite completely in 3-4 Days, it's great.

If anyone likes to try it and post the results would be interesting see it

Hector

Ich isn't always necessarily there. But what I think was meant by "always there" is that if your fishies immune systems happen to be weakened, and they get ich, then that ich was always present. Ich can be introduced to your tank without ever knowing, until/unless your fish get stressed.

Gradual temperature changes won't stress the fish to the point of them developing Ich. Sudden temperature changes, on the other hand, particularly sudden downward temperature changes, can be devastating in this regard. Don't forget that in the wild, the temperature of a fish's home isn't nailed to a specific temperature to within 0.001 of a degree as if thermostatically regulated: plus the temperature of the home waters of fishes such as Corydoras experience a temperature drop when the first rains of the rainy season fall, and for these fishes, this is actually a stimulus to spawn. But, the temperature drop isn't a sudden one. While you have several million gallons of rainwater landing on the rivers in the typical Amazonian Cory habitat, they're landing on rivers containing billions of gallons. Thus the temperature change is gradual.

Plus, any changes should be implemented in steps, no more than 2°C at a time, unless there are special reasons for doing otherwise such as stimulating certain specialised hillstream Corys to spawn.


Panda Catfish fan and keeper/breeder since Christmas 2002

Unless your pour water from the LFS to your tank, the fact that ich is in an established tank is limited unless you add fish.

Ich can last in your aquarium for about 6 weeks-8 weeks. Meaning, that it will be present for 6-8 weeks after you add fish, cross contamination of water with ich or fish sick with ich. After that, the ich would most likely be gone from the water.

Ich is somewhat like a flu. After we get it, we become immune to that specific strand. But since ich is in the water for 6-8 weeks, it has that time period to find a new host, form a new strand, and infect you again. This is where adding new fish allows the ich to form new strands, infect the new fish, and infect current fish.

I have never ever had a ich case that lead back to a temperature change. Temperature changes usually will only shock a fish slightly, I doubt it would cause significant damage unless you throw it from very cool, cold water to warm water, or something of that genre.

If ich is not in your water, a temperature change would most likely affect your tank temporarily unless you have sensitive fish such as rams or discus (I wouldnt even consider angels sensitive)

I belive ich is caused by the fish being stressed, but ich needs certain eliments such as copper and other elements to feed ich so that it may grow.

There are many types of stress. To name a few:

Temperature Stress or Shock

Fish don't self regulate their body temps as we do. It is governed by the environment. If your body temp plummetted from 98.6 down to 94.6 in mere seconds, and remained that way for several hours - you would get stressed too. Dr. Edward J. Noga, Professor of Aquatic Medicine recommends limiting temp changes to 1F daily for optimal health and least stress related to temp change. He discusses how immunity drops while the body deals with any stress and how it can take a full day for the fish's immune system to get working well again after any stress. Chilling, for whatever reason, makes them susceptible to ich and velvet.

pH Shock

Exposing fish to no more than 0.2 change in 24 hours or 0.4 max in cases where a tank is crashing.

Osmotic Shock

Going from little salt to highly saline conditions or vice versa

Here is a really great read on Stress - It's Role in Fish Disease by the University of Florida Extension Service:

http://edis.ifas.ufl.edu/BODY_fa005

This is a keeper so I highly recommend saving the link or printing it out.

Diane


Last edited by Cory_Di at 27-Feb-2005 11:06