After much reading and very mixed reviews I decided to give this a go as my local aquatics shop said my little goldfish had a tiny fungal growth on its fin. So to try prevent it getting any worse, use this. Reading reviews I was so scared to use and not sure about getting the correct dosage. I decided to start at a 1ml dose for my 17L tank and see how the fish react (2 gold fish, only 1 showing signs of any growths). The bottle stated to remove the carbon filter from the tank, so I took that out of the filter, turned it back on and dropped in 1ml of the product. Waited anxiously and the fish seemed fine. 24 hours later I came to do the same and I kid you not, the growth had shrunk to a tiny speck! Continued this for the full 7 days as recommended and then did a 50% water change and both fish are totally fine and healthy. I also removed my live plants during treatment even though it said plant safe I didn't want to risk. But, I did separate one plant and add a drop to that to see and it did actually survive so it probably is right! I just didn't want to take my chances and lose all of my greenery! My advice using this treatment is to give a very low dose and see how the fish tolerate it. Don't go throw in 5ml like it says! 1ml did my 17litre tank and treated the fish perfectly.