Can’t get rid of Ich

[duanes]

Immunity helps, but in a closed system like a tank (even what some aquarists consider a large one) or pond, the limited space allows for constant reinfection as the parasite population increases, and the glut of hatching parasites easily over whelms immunity.
Each ick spot can produce 100 new ones.
When I get wild fish here in Panama, about 1 out of every 8 or 10, has some parasite imbedded in them, (ick, Lernae, etc) but in nature are not really problematic.


So if I even notice 1 spot, treatment is needed.
For me, that means salt, that osmotically challenges the newly hatching parasitic larvae, but as in the case of the tetra above, physical removal of adult Lernaea, because as adults osmotic (saline) pressure is ineffective.
In both cases above, I added about 20 gallons of sea water to the 180 gal tank, which killed all emerging parasitic larvae.
And here in Panama, because natural midday water temps are often in the 90Fs, raising temp is a useless endeavor.

 

[Redshark1]

Thanks everyone for this discussion it is helping me to understand what was happening in my case all those years ago. I'm not yet fully conversant but thoughts are coming together with your help.

I have always thought that a dormant stage would be very useful to the Ich parasite in order for it to survive inhospitable periods such as drought, our chemicals etc. It would also assist transport on animals, nets, other materials and in water, air etc. It just makes sense and is present in many microorganisms. But the literature that I have seen denies this resting stage exists.

As I understand it the immune system relies on white blood cells to travel to the site of attack and destroy invading pathogens. I can see how the immune system could be overwhelmed by massive multiple attacks by Ich. I understand that stress suppresses the immune system which presumably lowers the number of white blood cells (and maybe other strategies for dealing with attacks).

I also see how a closed aquarium system is very different to a river, say, which could flush away most of the pathogens and make fish to fish transfer more difficult.

Somebody told me, not too long ago, that a UV steriliser worked for them to kill the free-swimming infectious stage of Ich instead of chemicals. Others swear by elevated temperature and/or salt. I used chemical and elevated temperature combined to achieve success.

So in my case described in my earlier post, my use of chemicals over an extended period killed all Ich by killing the infectious free-swimming stage over the whole hatching period preventing reinfection. Then, my fish were never subsequently infected by Ich because either their immune systems were able to deal with any future attack OR no future Ich was introduced over the next 27 years.