Disclaimer: IANAL
If you're wondering if you can treat your fish food with garlic extract, without being sued for infringing on somebody's intellectual property, the answer is yes.
My search on the USPTO database did not turn up any results for awarded patents, and even if it did, you'd still be able to make your own. A patent does not prevent you from replicating a patented invention for personal "research" in order to verify the claims made in the full text of the patent.
Additionaly, if you chose to treat fish food with garlic extract without any preservatives, you'd have a superior"Materially Different" product than Garlic Xtreme.
