The grayling (Thymallus thymallus) is a species of fish that is a member of the salmon family, yet shares its spawning time with our native coarse fish. A relatively short lived species at 10-12 years, it is one of our most impressive! The grayling has a giant vibrant dorsal fin that is very similar to a sail fish. Males and female grayling can also be identified by this dorsal fin when mature. As a pond fish they require high oxygen levels and cooler temperatures so a deeper pond would be needed for these fish with high oxygen. Most koi type ponds are fine and I keep these myself with Koi. Aggressive feeders and truly stunning native fish!