I moved my 24" goliath tigerfish last week and it wasn't too bad.
I did it in the middle of the night after the lights had been off for 4-5 hours so the fish was a little knocked out...had to catch it quickly though.
Drop the water level way down, to about the height of the fish, top to bottom. That's what I do every time I change the water and the tigerfish always calms way down. If you leave the water level like it is, all your fish are going to launch straight out and it will be RIP fish collection.
Put in extra aeration to help the fish breathe easier when the water is so low.
I used a super thick, long plastic bag to scoop it in...that was pretty easy.
Don't use a net or towel like all these other people are saying because that will break the tigerfish's fins (especially the dorsal fin) and they will never grow back straight. Look at all pictures of the small ones you see with this...it never goes away!
A super thick bag is your safest bet
Then I transferred it to a 30" cooler with airstone running and got it quickly to the new tank...about 10 minutes down the highway.
Since your new tank is right there, no need for you to use a cooler...just make sure you have a bunch of thick, strong bags.
The fish was in shock by the time I got it to the new house...it was upside down in the cooler and I thought it was toast.
However, it flipped back over in a minute after going into the new tank and it's back to normal now...use lots of aeration and add some rock salt in the new tank to help it breathe easier.
I've moved the same fish 1 1/2 years ago and also had good results this same way.
I moved my 23" armatus back then and that was a snap...used the same bag and cooler and popped it into the new tank. These fish don't seem as sensitive to transport as the tigerfish.
Your best bet is to move one fish at a time and see how it acclimates before you try another.
BTW, before you move the tigerfish and armatus, get all the other stuff out of there first: arowana, turtles, tigrinus, etc...
Be careful with your fish...you hardly ever see or hear about a tankful of these at that size...awesome collection and good luck with the move!
I wish I could help you but I don't live in Hong Kong anymore.