Clove oil is a natural sedative for fish, and it can be used to make them sleep. This essential oil works by producing an anaesthetic effect on the fish, which causes them to become drowsy and eventually fall asleep. The active ingredients in clove oil are eugenol, caryophyllene and other sesquiterpenes that produce this effect when they come into contact with the gills of the fish. Clove oil has been used as a sedative in humans since ancient times and it's also known for its calming properties, so it makes sense that these same qualities would be useful for inducing sleep in aquatic animals too. It's important to note that while using clove oil can help put your pet fish to bed quickly, you should always use caution when administering this type of medication, as too much could result in toxicity or even death if not monitored properly. Additionally, you should never attempt to medicate any kind of wild or farmed fish without consulting a professional first.