Moving house and having large fish tanks is a bit of a logistical nightmare, i have been through this process a couple of time and it does not really get any easier!
I find it best to plan well in advance and if possible ask if access to the property a day or two earlier will be allowed so that you can set up temporary tanks or even a few large clean plastic tubs or large containers with dechlorinated water, heater and a basic filters with media from established filters so that you can move the fish straightaway into those while you move and set up the large main tank/s. This would make things so much easier if access can be granted.
Or if you can have access to both properties, meaning not having to leave your old place striaghtaway then this will help greatly and give you much more time to do this move rather than trying to everything in one single day.
Moving the tanks themselves, well, there are a few ways of doing this, what I do is take some of the substrate into buckets, keep this substrate wet/damp so as to reserve as much BB as possible, and put some or all of the plants into fish bags with a little water and empty the tank as much as possible for the move itself.
If you try moving the tank with substrate and an inch or two of water, this CAN be done and I have done this before but done at your own peril (so stressful moving tanks in this manner tbh) as its so easy to crack the bottom pane of tank glass with the weight of substrate, plants and what little water is in the tank plus the fact the tank is heavy enough as it is when its empty, never mind trying to move tanks with the above in it!!
As we all know, setting up a tank is not a quick and easy job, so be prepared to put in a number of hours to set up the tank, but the fish should be fine for a day or two in the containers provided its heated and filtered. Don't feed them during this process btw, they will be fine without food for up to a week if nice and healthy.
An as for moving the fish themselves, I would advise purchasing or getting a number of varied sized fish bags from LFS or online and transport the fish in those, put in about one third water and a select few fish and fill up the remaining two thirds of the bag with air and tie off firmly and add a elastic band over the top of the knot, this helps ensure the bag remains inflated and no water to escape.
Put those bags into the buckets you have, cover with a towel or something as fish are less stressed in the dark rather than bright daylight.
There are a lot more to this but have tried to keep to the main points to keep it simple as possible.
Good luck with the move and do let us know how you get on.
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