It is not, high temperature in the proper range stops the reproductive life cycle of ich. That's normally in the range of of 30 to 31C when it comes to fish tanks as higher is dangerous to the oxygen levels and lower won't kill ich. ...Slowly bumping to that temperature with plenty of surface agitation can actually work alone without any meds but it is easier treating with meds than temp/salt treatment, unless you have med sensitive fish. I treated a clown loach and a bunch of platies with temps and salt alone. The problem with temperature treatment is that you need an accurate thermometer and an oversized heater to actually keep the temperature stable and above 30C.
I am starting to regret I posted in this thread.
To reiterate:
Ich lifecycle is temperature dependent. Higher temps mean faster lifecycle. At least until a certain point where the organism is actually affected and maybe killed.
Sources on what this specific temperature is vary from 30C to as high as 36C. That is why I wouldn't recommend heat treatment alone; and as you mention you'll need to make sure your equipment can reach the target temp (whatever it is) and keep it stable for several days, in the entire tank. That is without delving into the stress it applies to already sick fish, not to mention plants etc. So no, I wouldn't recommend heat treatment as a sole action. I actually think that it would do more harm than good in a lot of cases.
When OP raises temperature to 26 degrees without additional treatment ( be it salt or Esha Exit or some third med), that is counterproductive.
I spend a couple of days reading about ich when I got it (and not only at skeptical aquarist btw); and what I took away from all of this is:
- Get whatever meds you like, Esha Exit is as mentioned fairly safe if used as directed. Salt can be fine, but make sure all plants and fish can handle it if used in tank.
- Raise temps to around 28-29 degrees over a day or two. I went for 28, and hit it fairly square. It is not set in stone, just get somewhere in the vicinity to speed up the ich lifecycle to around 4-6 days. Provide additional aeration if neccessary
- Do a large waterchange, be sure to maintain your target temp.
- Then start dosing. Esha Exit treatment runs for 3 or 4 days (can't remember exactly), after that you should:
- Do a large waterchange, be sure to maintain your target temp.
- Run a treatment again.
- If you want to be certain you get every last theront repeat the above two steps once or twice more. I did only 2 consecutive treatments, and have been ich free since. I'd probably recommend at least 2-3 consecutive treatments at the mentioned temp.
This worked for me, in a tank with plants, fish and various inverts. I also didn't use temperature alone as some kind of treatment, but as a tool to make sure that the ich hit the free swimming stage during treatment.
So it was needless to operate with temperatures that would be potentially harmful (at least in theory most tropical fish should be able to handle 27-28 degrees in a shorter period, it really comes down to an estimate of the particular fish). If you for whatever reason can't raise temperatures, be aware that treatment should run longer than at higher temps. For decidedly coldwater fish we are talking several weeks.
