One of my Oranda Goldfish died and I dont want the other one to be lonely?

I've had the two orandas for about 5 months. The one that dies was about 5/6 inches long and the one that survived is about 4/5 inches long. They didn't die from bad keeping but builders were working on our street and they were VERY noisy. There going to come back and i don't know what i should do, i don't want my other fish to become ill as well. There is a pet store nearby but I cant give it to them while the builders are here because I know they suck from experience. I cant get any more fish now for a month or two because they might dies from stress because the builders are really taking their time. What do I do?