Hi,
I just saw this forum thread because I was wondering if tea tree oil in the water would help with an algae outbreak.
I was surprised by all of the rude replies you received. I would like to point out to all of those know-it-all aquarium experts that a common product by API, named Melafix, had the active ingredient listed as "Melaleuca 1.0%". This Melaleuca is just another name for tea tree oil.
So all of those people who were rude to you can go back to their Beta Bowls and perhaps try researching something before they so flippantly answer someone's question, which they obviously knew nothing about. This is why forums can't be taken too seriously. So many people want to be experts and think they are. And on the web, you can be many things.
Of course tea tree oil would have to be used with caution. It is a little late for this blog but my recommendation is to use a product like API's "Melafix" which is commercially controlled concentration and follow the directions that is printed on the bottle.
I would like to point out that using any "treatment" product, like Melafix, is not safe for fish, period. If there is a specific issue affecting the fish, such as a disease, bacteria, fungus, etc, and it can be reasonably accurately identified, then an appropriate treatment that is likely to be effective may be used. But to use any of these so-call general "treatments" on a regular basis is not at all good for the fish. Or the biological system of the aquarium if it comes to that.
The reason is, that any and all substances added to the water in the aquarium will get inside the fish. This is due to osmosis through the external cells and the gills. What enters then gets into the bloodstream and internal organs. To perhaps make this clear, it is comparable to injecting a person with any substance directly into the bloodstream. With fish, unlike all terrestrial animals (exception being amphibians), every substance in the water enters the fish; with terrestrial animals, they breathe air, and while toxins in the air can certainly enter the bloodstream in the lungs, the process is much different. Water is also a more rapid transporter than air, due to the fish's physiology. So, for healthy fish free of unnecessary stress, nothing should be added to the tank water except what is essential (conditioner for example, treatment for specific problems/disease, natural plant nutrients if necessary and less rather than more).
At the very least, even if the substance is not toxic, it is almost always stressful. The fish's physiology and metabolism has evolved over thousands of years to function best in a very specific environment; here again freshwater fish are like no terrestrial animal in this significant dependency on the aquatic environment. Stress occurs when anything affects this relationship, and stress is the direct cause of 95% of all fish disease.
I have used Melafix only once (as a specific treatment), and according to the instructions, yet it was clear the Melafix seriously impacted the fish. I have never used it again, and never will; for one thing, like most of the general "cure all" remedies, it is not going to be particularly effective, and there is always a better treatment that will be effective and likely cause less, certainly no more, stress by its use.
Aside from that, I also agree with Steven's post on the issues he mentions. Here again, there is no benefit to such products, but there will be detriments.
Byron.