yup that is a good guide, i usually have a copy of that in my rucksack.
http://web.ukonline.co.uk/aquarium/index.html
but here is a site that has colour photos and lists the fish by family...
just scroll down and find the fish your looking for...
http://www.fishbase.org/search.php
for a more in depth search try this site, but it might take a bit of time to figure it out and aafind the fish you are looking for, but i could nearly garentee you'll find it here...