Oh, you got the expensive ones! My goldfish are the 10 for $1.00 feeder
fish. They're 4 years old now. Started with 20 ( yeah, a whole $2.00 worth )
must have 50 or so now, 2'', the young-uns, to 10", the original ones. Like
I said in previous post, I don't feed them ANYTHING at all when the water
temp is below 50o F. It's not so much a swelling of the food thing as it is
a digestion thing. Rumor is, that below 50, the bacteria in their stomach
goes dormant and as a result food will rot in the stomach (bad thing)
leading to belly up syndrome. My fish, the 50 goldfish and 8 koi, go from
mid October to around April without ANY food. I suppose they eat the
occasional bug and maybe some algae, but nothing 'manmade'. They do just
fine.

Paul