Great caution to anyone who uses it. This product claims to contain 66mg praziquantel/mL. It does not specify if it contains any other chemical ingredients, which it seems it must eventually contain. Praziquantel is safe for use in a reef aquarium. Unfortunately, after using it in my main aquarium, many of my corals melted. It is unacceptable not to list all the ingredients of the product, and I believe it is also illegal in the EU. There were no mentions in the instructions to use it only in a secondary aquarium, only on their website. Not even in the "CAUTION" section is anything mentioned. The only thing mentioned in the instructions is that there is not enough evidence to determine if it is safe for corals. If it was just praziquantel, there would be enough evidence. Obviously, it contains something else.