I have had an otter in y pond lazt night lwhick has killed three of my koi I havE had them for over twernty years sp I aM REALLY PEED OFF the 4500 gallon pond is netter and is in ground and three feet above Does anyone know if I get some galvanised metal netting would this prove detrimental to the remainign fish. My two largest who r over 35 are undamaged but the three remainign have damage Any suggestions as to what I can add to prevent disease without affecting my filters

YOur input wud be appreciated