Welcome to the forum. First off, I have a few questions for you. Did you cycle the tank before you added the fish? Are your Goldfish
the fancy kind (golf ball shaped with double fins) or the common type (looking like regular carp-like fish)?
The cloudyness is probably a bacterial bloom. It can happen when a tank is cycling. It could also be the fish waste. Goldfish
are messy little buggers and need heavy filtration as well as a large tank. The bubbles are probably from the air pump. If you want to try to clear up the bubbles, turn the settings down.
Actually what Goldfish
like is a constant temperature. I keep mine at 75F. If your tank will constantly stay 68F then you would be fine to leave them there. Just remember, Goldfish
metabolism is determined by the temp of the water. If you want them to grow faster, turn the temp up.
I'm very sorry you got bad information, but 7 Goldfish
cannot live in a 30 gal tank. Goldfish
get large and have a very heavy bioload (produce a lot waste). You will have problems with disease and stunting if you leave them there. Most people recommend 75+ gal for 7 fancy Goldfish
. For a 30 gal most people recommend only 2 fancy Goldfish
. A beginner's rule of thumb is 20 gal for the first fish and an additional 10 gals for every other fish. You may have baby fish and think they can fit, but trust me, in no time it will seem like they are bursting the tank.
I think the best thing you can do in your situation is return all but your two favorite. Or you could return them all and get different fish. Many of the tropicals remain rather small, so you could fit more tropicals in your tank than Goldfish
. Everyone here would be more than happy to help you stock your tank with tropicals.