i kept them as a child,we used to catch them from the local pond,
they would eat anything the gold fish did not(yeah i know how bad in with g/fish)
but i was very young……trouble was said gold fish wanted to eat the
stickle back and it got lodged in the goldfishes mouth,rescue was successful,
they went to live in the out door pond,where they could be better observed
with breeding :-D which they did very well,to the point of taken
back to original pond as they were taking over the garden pond.
lots of waffle no help sorry.