somethings wrong with the fish

Question
i got my fish for almost 1 week now, they are energetic and used to swim around the aquarium but for some reason they are staying at the bottom and hiding. i also have a betta but it seems not healthy these last 2 days, he doesn't wanna eat and sometimes swim wildly in the aquarium and then stays at the bottom hiding and it has white dots on his fins, what could that be?

Answer
Hi Kate
I assume the tank is fairly new as well?  It sounds like it's suffering from new tank syndrome.  Basically, ammonia poisoning.  That would explain why the fish are staying at the bottom, swimming wild in the tank, and hiding.  Here's a link that explains it a bit better, it's called the nitrogen cycle:

http://freshaquarium.about.com/cs/biologicalcycle/a/nitrogencycle.htm

You're going to need to do daily partial water changes until the tank finishes cycling, to help dilute the toxins in the water.  You should also pick up a good test kit that tests for ammonia, nitrite, and nitrates so you can monitor those levels during the cycle.  

The white spots sounds like it's ich.  Ich is a protozoan parasite that infects fish when they're stressed.  It looks like the ish were sprinkled with salt, usually starts on the fins/tail and eventually spreads to the body.  There's several ways to treat ich, but without knowing what other types of fish you have, I can't recommend one for you.  Here's a few good links on ich:

http://www.peteducation.com/article.cfm?cls=16&cat=1791&articleid=2421

http://en.wikipedia.org/wiki/Ichthyophthirius

http://www.aquahobby.com/articles/e_ich2.php

What types of fish are in the tank?
And how large is the tank?

Christy