My fish all died within 30 minutes

Question
I recently acquired a freshwater fish tank. It is only a 2.5 gallon fish tank, since I am new to fish and have no idea what I am doing. I feed the fish every morning and night. We bought some fish for the tank, those fish being tetras ghost shrimp and a snail. About 4 days ago, the water in my tank began to get slightly cloudy. It wasn't a thick cloudiness, but more like a light fogginess, and I thought that it was just a little algae. 2 days ago, I realized the snail, who is supposed to be eating my algae, was dead, not just floating, so I took him out. Today, that water was so cloudy that you could barely see through it. I am not sure why it is getting cloudy, because I have a very small tank with a 5 gallon water filter. I don't over feed the fish either. Around 9:00 p.m. this evening I noticed my ghost shrimp (4 of them) were jumping out of the water and sticking themselves to the top of my aquarium, above the water. I only recently got the aquarium and I have never had fish before so I don't know if this behavior can happen sometimes or not. I got them back in the water and they seemed fine. At around 9:30 I went to check on them again, and 4 of my fish were dead. I only have 6 little tetras, so this is nearly all my fish. I took the two remaining living fish out and into clean water, and one promptly died. The other fish seems to be doing fine in the clean water so far, but I am worried this last fish won't make it throughout the night. I have no idea what I need to be doing with these fish. What is the correct temperature for fish? What could I have done differently to save them?

Answer
Hello Laci:  New tanks have to cycle before you can add fish.  Tank water is a balance of beneficial and non beneficial bacteria as well as chemicals.  For fish to survive in tap water or even bottled water the water must sit for a period of time until a sufficient load of beneficial bacteria can grow.  The reason is this: The chemical levels in tanks can reach levels that will kill fish.  Ammonia, Nitrite, and Nitrate levels grow from things like fish poop or extra food that begin to decompose.  The snail probably died because there is not algae in a new tank and even if there were snails, and other bottom feeders have to have a supplement in their diet to help keep them healthy.  Algae wafers work well as a supplement.  The cloudy water is due to the tank trying to cycle and the cloud is actually the result of the bacteria trying to reproduce.  A 2.5 gallon tank can house no more then 2.5 inches of fish.  So six tetra, four ghost shrimp, the snail and whatever else you may have had in there represent a significant over population for a tank of that size.  If you didn't have an air stone and air pump they may have all died from suffocation.  Tropical fish like to be in water that is between 78-82 degrees...but be warned that without a air source warmer water can kill fish too...because warmer water holds less oxygen then cooler water.  So if you are to be successful in keeping fish you will need to make sure that you have a filter, air source, and a heater.  You should also find a good book to help you with tank set up.  There are many good texts available.  dave