Well there are a lot of informational sites for catfishes...in fact its too much of a burden to post them all here

I will post some anyway...

This one is actually an import export company and provide no information about the fish. Plus u have to verify them yourself just to make sure its the real thing (correct name). a good pictorial tat u can use for reference though.

The names of the sites are listed at their URL so u can guess who is where. Do be reminded that you are not sent to the "home" page so u shud navigate by your own...

http://www.amazon-exotic-import.de/G.../SAUGWELSE.HTM

http://www.scotcat.com/loricarleft.htm

http://www.jjphoto.dk/fish_archive/mall3.htm (this one loads very slow)

This is the official place for Datz references or uses it. Not much info i guess coz i can't read deutsche
http://www.transfish.de/Loricariidae.html

This one is for corydoras spp.
As usual pictorial only unless u can read japanese...lotsa fun activities too...like origami corydoras project...great for your kids.
http://www.nettaigyo.com/corydoras/illust/index-e.html

This is Ian Fuller's own website...lotsa info on the corydoras spp.
http://www.corycats.com/