Why would my fish stay near the pump?

My fish just goes to the bottom of the tank, (a href="http://images.google.com/imgres?imgurl=http://www.aloha-aquariums.com/catalog/046798291329.jpg&imgrefurl=http://www.aloha-aquariums.com/servlet/the-2469/Tetra-3-Gallon-Aquarium/Detail&usg=__uB7GO1yuBt9BbQAliwidfii49wk=&h=600&w=591&sz=148&hl=en&start=2&um=1&tbnid=lwH3yyI4ydyKLM:&tbnh=135&tbnw=133&prev=/images%3Fq%3DWhisper%2Baquarium%2Bpump%2B1%2Bto%2B3%2Bgallon%26hl%3Den%26um%3D1" rel="nofollow"http://images.google.com/imgres?imgurl=h…/a its the pump ), and basically it doesnt move. It moves when I turn on the light though. Please help! I'm scared..