Re: HELP: GUPPIES HIDING
#2
The filter media in the new/temporary tank would need to be cycled, otherwise there is the possibility that the fish will be experiencing the effects of ammonia. To do this (if you haven't already), all you would need to do is move a small portion of the filter media from the main tank's filter into the new tank's filter. In essence, the main tank's filter will have enough filter media to process the waste of its inhabitants, so, if you move across roughly the appropriate percentage of that filter media for the two pregnant guppies, that should suffice (e.g. if there are 8 guppies altogether including the 2 pregnant ones, then move across ~25% of the filter media into the new tank's filter).
Is the filter outflow particularly strong .v. the size of the tank? I've had fish hide by the filter due to being buffeted about by a strong outflow, and have addressed this by either turning down the flow or putting a small piece of filter media over the outflow nozzle to reduce the strong output.
As you have rocks/plants and potential hiding places for them, I can't think of any other particular reason for their behaviour, other than possibly wondering where their tankmates are (but I do think you've done the correct move by moving them across to give birth in peace) or possibly nervousness about the impending births.