raising pond fish indoors

I've had a pond for several years with half a dozen Goldfish/Shubunkin
and a couple of Orfe. Each year I see lots of small fry in the
shallows but that's all I ever see, presumably they become tasty
morsels as they never make it through to the following year.

So I had this idea (well two)

First was to rescue some of these fry and move them to an outdoor
water feature such as a barrel with small pump and a few small plants,
keeping it through the winter might be a problem though.

My preferred is to house them in an indoor tank and after growing them
to a size where they won't become fish food, return to the pond in a
year (or maybe two).

As I know nothing of keeping indoor fish (though I'm reading lots and
finding all the faq's and websites I can) is the second option
feasible? Having visited a couple of Aquarium stockist's I have got
differing opinions, one says yes its ok the other says no they would
be hard to feed and water temperature differences (pond to tank) would
be too stressful. But I guess many of you folk breed indoor fish so
what do you feed them on?

I was hoping to set up a small 2ft tank with pump/filter and have it
running with no fish for a few weeks to stabilise so when the fry
appear there would be an environment ready to take them.

Has anyone tried this or could offer any advice?

many thanks

Minty