In the absence of a froggy female, frogs will mate with the nearest shaped alternative which may be a goldfish! Frogs clamp on to females for days at a time to fertilise the frogspawn. If a frog finds a fat fish, like a female frog, it will clamp on. Most fish will survive this, unless the frog happens to clasp their gills. We've got so few frogs left in this country, that we really shouldn't do anything to discourage them from using our garden ponds. If a male toad clasps another male it makes a release call, a kind of squeak, which tells the mating toad to let go. As fishes don't make this noise, they continue holding on.