Sturgeon & Tench Sinking Pond Pellets. For sturgeon in mixed carp ponds. This sinking food is ideal for Sturgeon when mixed with Koi carp etc. It can be fed to your fish all year round as it has a low (for sturgeon) protein level and added wheatgerm to reduce the chance of harm to other breeds such as Koi carp that cannot tolerate high protein levels in the colder months.