We often hear that releasing goldfish and similar fish into the wild from home ponds and aquariums is a bad idea because these fish are not native, i.e. are invasive and can cause environmental damage and spread disease. Yet, there is no British native carp - the crucian, mirror, grass and other carp are all introductions from overseas but they're not regarded as the bad guys. Does anyone know the reasoning behind this goldist attitude?
Thankyou.