There seem to be plenty of tips on building new ponds but very little
on increasing the size of an existing one.

I have a six year old 8x4 foot pond that I'd like to double the width
make it oval(ish) to about 8x8 but what to do with the existing fish?

It currently holds 3 Orfe 3 shubunkin and a couple of grass Carp (that
you never see). Orfe are 9 inches or so long the others about
6-7inches. All fish are timid as hell I think it was a bad choice from
the start, but I assumed as Orfe were surface feeders I'd be seeing a
lot of them - not so. Venture anywhere near the pond and they are gone
and the Shubunkin go with them!

How long would I have to rest the new water before reintroducing the
fish if I added something like 'Freshstart'?

Would the fish survive in a polythene lined bathtub 4x2ft if I put the
pump in there to slowly move the water around whilst the construction
goes on. How long would it be safe to hold them like this?

If after completion I added some smaller Goldfish would they help coax
the Orfe out of hiding to feed or would they just go and hide with all
the others?

If anyone has any experiences to share I'd be grateful to hear them.

thanks

Bob