Nile tilapia
A study conducted by the Aquaculture Institute looked into the effects of cannabis oil on the metabolism and immune system of the Nile tilapia "Oreochromis niloticus". They found that cannabis has no measurable effect on the white blood cell count or plasma protein concentration, and therefore has no effect on the immune system of the Nile tilapia. However, the tilapia that were fed food pellets laced with THC demonstrated a higher food conversion rate. This higher food conversion rate lead researchers to believe that THC increases the metabolic rate of Nile tilapia.