hello, for the first time i will over winter  my Koi and gold fish in large container in the garage. Pond not deep enough and the fish out grow the aquarium. i have a filter set up plus UV light. My question is, do i also need to set up a light system, the garage gets very little day light. any other comments are welcomed.

thanks, would 4-5 hrs be enough?

How large is the container? Koi need massive ponds, so I find it hard to imagine a container big enough for them?

You can't acclimatise the fish, it is far too late in the season, the shock to the temperature if they've been in an aquarium in a house all this time would make them seriously ill or kill them.

I would suggest keeping the fish in the tank they come from/or a large plastic tub in the house, for a little bit longer and introduce them to your pond when it's much warmer But do make sure you aren't over stocking your pond by adding them!

Also as for the Koi just be sure to keep the water quality good, may I ask how deep your pond is? If it isn't deep enough to over winter them, are you sure it's deep enough for them generally?