Yes, you will need an Airpump and an airstone. You want to have the airstone "in" the base of the tube, so that it sends lots of very fine
Got through my second water change and first rain storm. The sipons worked perfectly and the levels are stabalizing. I added
I had 2 of the south american bumblebees for 5 years.. their max size is 3" while the asian is twice of that. None of my fish will outgrow my tank.
It depends on the type of goldfish you have. Comets, Koi and such are fine. Some fancy goldfish can't take the cold as readily. I'd google temp tolerances
You should be fine if you stick wit the above.