Goldfish and White Clouds

Question
I've just had a case of my goldfish killing the white clouds.  This is not simply a case of missing fish (oops gulp sort of thing) but the clouds being torn apart.

I initially had two tanks: 1 with goldfish, zebra danios and pepper catfish the other with goldfish and White clouds and pepper catfish.  About 6mths ago I merged the two tanks into one large tank.  Everything has been fine and they seemed to get along great.  There is plenty of weed for the smaller fish to hide.

Yesterday, my tank floor was littered with mauled bodies of white clouds.  Some were missing head others had be torn in half.  There are only 2 remaining alive.  What has caused this?  I've had goldfish for years and never had this sort of problem (I did have some tetras go missing, but I suspect that was simply a gulp in error!)  The pet shop seem to think it's territoriality, but 6mths down the track?

What do you think?

Thanks for your help.

Answer
Hi Prue,
That is quite bewildering. My best guess is the goldfish have tried to eat the little minnows. Fish can be savage and unpredictable. Its a sad thing though. You never know what might happen. But since goldfish are usually larger than the minnows they would have been fair game for the goldfish.  Usually these two species are compatible except when the goldfish grow large enough to try to eat the white clouds.

I'm sorry to hear about the white clouds. Best to keep these two species separate.

Take care,
Karen~