Question
Dear Robyn

i have got a pond that has been established for about 5/6 years there was a goldfish of about 6-7 inches that had been living in the pond since it was set up & looked very healthy. The pond is home to at least 30 frogs possibly more. I noticed that the fish was not moving yesterday & went out to take a closer look upon further investigation I saw that it had got a frog latched to it covering its gills, the fish looked dead & other frogs would come from time to time & join in holding on to it. there was no way i could fish it out as the frogs at the first sign of movement would go to the bottom of the pond taking the fish with them. This morning the fish was laying beside the pond, it had not been eaten. did the frogs kill the fish? i would like to replace the fish but do not want the same rather gruesome thing to happen again. i also have a number of decapitated frogs around the pond again this year do you know what is attacking them.

Answer
Do you know what species of frog that they are?  How big are the frogs?  What is your current pond temperature?  The frogs here aren't yet active.  Bullfrogs can eat small goldfish but most other frogs won't touch fish.  Frogs normally only go for living prey and swallow it whole.  My opinion is that the frogs probably did not cause the fish to die.  I hypothesize that the fish was ill and probably not completely dead, maybe thrashing a little but not moving much.  Then, the frogs maybe saw the movement, and since the fish was too weak to fight them off, they may have then grabbed the goldfish that was too large to swallow.  Them then grappling with the frog could have finished it off.  It's certainly possible that a larger frog tried to swallow the fish whole but couldn't and then spit it out dead.  These are all just guesses.  

If it's warm there, frogs could have moved the fish to land but, if not, perhaps another predator moved the fish.  Since you've had some decapitated frogs, that also indicates another predator.  Frogs will eat frogs but normally eat all of them.  Both raccoons and cats sometimes will eat just part of a frog.  Most other predators eat the whole animal.  It's the raccoons that tend to be the most messy.  I've been assuming that you're in the US.  If not, then what I've said may not hold.

What other fish do you have?  Are they ok?  How big is the pond?

My frog page is at http://www.fishpondinfo.com/frog.htm

Here is a photo of a large bullfrog trying to eat a large goldfish:
http://www.fishpondinfo.com/photos/amphibians/bullfrogs/frogfish.jpg
Yikes!  I have a few bullfrogs and have never seen them eat fish (at least not while I was looking).

Good luck!