Ideally the pH level for goldfish should be maintained between 6.5 and 8.5, so your tested pH of 7.6 in the new tank seems ok.  Make sure the temperature in the new tank is about the same as the water in the vase, where the goldfish are staying.  Did you use a water conditioner to remove any chlorine or chloramine that might have been in the tap water you used to fill the tank.  Most public water supply will be treated with chlorine or chloramine  to make the water safe for humans to drink, but these chemicals are very toxic to fish. Chlorine will usually evaporate in 24 hours , but the only way to remove chloramine from tap water is to use a water conditioner.

Ideally you should allow at least 48 hours for the water in the new tank to stabilize before putting your fish in there. Some people also prefer to cycle the tank first before adding the fish. Cycling the tank will help to build up beneficial bacteria that will to break down toxic fish wastes, which can build up quickly in a new tank.

Hi...I've had my 2 goldfish for over a year, 3 weeks ago I bought a medium size bottom feeder who died 1 week later. Since that time my 1 large goldfish has been acting very strange, he now won't eat and stays hidden under a large rock, the other goldfish which is smaller follows along and stays at the bottom of the aquarium.  Have I made them ill by bringing in the bottom feeder. The smaller fish at least will eat but then hurries back to the side of his friend.  Are they dying? Ifnot, what can I do to make them better? Is there some type of medicine I can purchase. The aquarium is clean and filtered. Please help!