Is my tank too small for 2 average sized goldfish?

This is about the same size: a href="http://www.google.co.uk/imgres?imgurl=http://image.made-in-china.com/2f0j00VULQMtgyuTBr/Mini-Fish-Tank-LV-320-450-LV-320B-450B-.jpg&imgrefurl=http://www.made-in-china.com/showroom/heatheryu/product-detailiAuQbEryRxoR/China-Mini-Fish-Tank-LV-320-450-LV-320B-450B-.html&usg=__LpEu9O-u1Rp_EAWGpl8IN4RVIhs=&h=287&w=325&sz=89&hl=en&start=56&zoom=1&tbnid=gSm-ov81xv4HQM:&tbnh=118&tbnw=120&ei=z6f7TbqHFo7B8QPHramqCQ&prev=/search%3Fq%3Dfishtank%26um%3D1%26hl%3Den%26sa%3DN%26rlz%3D1C1DVCJ_enGB374GB381%26biw%3D1280%26bih%3D709%26tbm%3Disch&um=1&itbs=1&iact=hc&vpx=109&vpy=372&dur=2631&hovh=211&hovw=239&tx=207&ty=120&page=3&ndsp=28&ved=1t:429,r:21,s:56&biw=1280&bih=709" rel="nofollow"http://www.google.co.uk/imgres?imgurl=ht…/a