So this is an established tank that has been moved? Ph is a bit low. However, it is not going to harm the livestock as much as a rapid change in Ph. Bringing your Ph up slowly is critical. It will take several days to increase it back to 8.0-8.2. One point every other day is a good goal to shot for. For now, try removing the glass tops on your tank (if you have them and your lighting until allows) and agitating the surface of the water with a powerhead. This will increase gas exchange and should raise Ph.
Some people are like slinkies...they serve no real purpose yet can still bring a smile to your face when you push them down the stairs!:p
Have a great day! Brian