Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Moving tanks that are still full of water, or even half full is not a good idea.
I would drain them and remove the fish, then slide the tanks onto the shelving. It is probably OK to move a small tank (10-15 gallons, maybe 20) this way, with substrate still in it. I would remove rocks. The lighter the thing you are moving the better control you have over it.
If you are moving to a new spot with the same tap water, and you are using tap water to fill the tanks then a 90% water change should not be a problem.
If you are using treated water of any sort (RO + minerals or whatever) and can set up a lot of it ahead of time, a 90% water change would not be a problem.
Otherwise save some of the water so the fish are not exposed to too great a change in TDS at the same time as the stress of capture, move, possible stirred up substrate and so on.
I would be more conservative with the fry. Match the new water with the old as closely as possible. 100% water changes are not a problem, but the parameters need to be really close. Take no risk at all with possible nitrogen spikes. The younger fish are less tolerant of ammonia or nitrite.