Why do my fish rest for days

I have owned my fish for about 3 weeks now (5 Goldfish) and for the first 2 weeks they were very lively and now they just sit on the bottom of the tank all huddled up together in a corner behind a plant. It has been about 4 days now i checked the temp. and its at 76 F. They get huge spurts of energy now and then and go zooming all over for about 15 seconds and then go back to the corner huddled up, and also swim lots during feeding. I am aware that fish "Rest" but for days on end? Whats wrong?

your suffering from new tank syndrome. im currently fixing mine :-P buy a product called Stability by Seachem and also Prime by Seachem. your fish are stressed out, dont add anymore for a little bit. your biological filter may not be established yet, stability will aid in establishing this for you. prime is like stress coat but better, it does everything stress coat does, but it also gets rid of nitrates and ammonia. goldfish let off a lot of ammonia which is horrible for the fish. you can find these products at just about any store. im going through something similar that you are, and i started using these about a week ago and all is back to normal. a suggestion i have is to get established with an actual fish/aquarium store. they have more knowledge than a general pet store. there is nothing wrong with petsmart/petco/pet supplies plus, or w/e you have at home, id just rather be going to someone that actually knows what they are talking about.