Q about getting donated plants

Hi All,

I have a question in regards to the 'safeness' of donated plants from
suspect tanks.
I work with someone who offered to give me some java ferns. I'm not
usually one to pass up something free, but last year when I was at
this person's house, I saw the tank. It pretty much reflected the
whole house.
The tank looked to be a 20gal. There were 4-5 goldfish in there and
there was so much green algae in there you couldn't even see the fish.
Should I be worried about them? I have a quarantine tank (yay!) set up
and obviously would house them in there before subjecting my pets to
them but I don't want to muck that one up if it can be avoided.
This same person also offered me his 20gal tank (fish are dead or..?).
It is currently sitting outside in -30 to -45 weather (should kill
everything?) and I'm wondering how well the sealing would hold up
after being exposed to those temps. Anyone have any thoughts?

TIA,
Trina
Yukon, Canada
44gal/tall/pent/fresh
http://mekong.connections.yk.ca/mila...LiquidZoo.html