Ich Immunity

[SubRosa]

Our fish live in the ocean."Ich" lives in the ocean.Yet most of the fish that come in show no signs of any external parasites and show no obvious symptoms.What causes the runaway outbreaks we experience in captive situations is environmental stress brought on by bad handling in holding and transit,bad water quality,poor diet,uncomfortable surroundings etc.That is why old established tanks often seem ich proof.Given good care and suitable surroundings fish are very resistant to disease.The fish are used to each other,and newcomers generally sink or swim without greatly affecting the more established residents.Unless the newcomers are real bad actors like Undulate Triggers or perhaps a Sohal or Clown Tang,in which case no tank is immune to the stress that can cause an outbreak.

[Paul B]

SubRosa, thanks for posting. It is true that the sea is full of paracites and most fish are exposed and infected even if it is only a very few paracites.
As a matter of fact, many fish also carry worms. My family has been in the fish business (fish for food business) for over a century and while cleaning fish we often saw worms.
Anyway, paracites are not a problem in the sea at all because of the water volume. After the paracite matures and hatches the offspring go off to find new hosts. In a tank the same fish is re-infected over and over and each time the paracite matures, they multiply exponentially. Eventually there are paracites all over the fish because they have no where else to go.
The paracites are just doing what they have to do and they have no where else to do it.
We introduced the little sucker into our tanks by not quarantining.
In a perfect world we would all quarantine everything and there would be no ich in tanks. Of course this is not always the case and we have ich. Fish have a few paracites on them in the sea and it may impart some immunity.
In humans we inject weakened disease organisms to ward off many diseases and if we did not learn how to do this, there would be a lot less of us around to keep fish.
It would be impossable for me to quarantine everything I put into my tank. I run my tank with a different method than many people, not necessarilly the best way, but I believe most tanks are too sterile. I use a portion of NSW which I collect in NY I also add local seaweed, amphipods, copepods, worms, shrimp, sponge, snails, urchins etc.
I also add bacteria in the form of mud. I feel that tanks are lacking in a diversity of bacteria. I do not advocate my methods as there are many successful tanks out there that do not do this. I do it because I like the diversity I get. I can lift a rock in my tank and see a variety of life that I would not see in a straight tropical sterile tank. I also feel it is beneficial to the fish and the reason that they usually breed and are seemingly disease resistant. If paracites were a problem in "MY" tank the fish would not be living 12, 15 and 18 years. Again, I do not advise anyone to run their tank the way I do. My tank is an experiment and not meant to be a beautiful chunk of the sea to decorate my home. Doing this in most tanks would lead to a crash or a die off due to ich.
The reason for this thread is to try to find a reason why some tanks can do this while some can not. If you look up "Ich" you will see all the people who have a problem with this disease and maybe we can come up with a solution for the betterment of the hobby.
Have a great day
Paul