Lebendgebärende Zierfische - Arten der Welt.
Manfred K. Meyer, Lothar Wischnath, Wolfgang Foerster.

Written in German, this book could be regarded as the Bible of livebearers. Loads of colour photo's of fish & biotopes, line drawings & maps. 495 pages on quality paper.
Written in 1985 I picked my copy up around 1990 for £19.95. I think this book is out of print but worth looking out for.

Aqualog
Michael Kempkes & Dipl. Biol. Frank Schäfer.

Everyone knows the Aqualog format of loads of photo's of different populations & variations of species & this book follows that format. It's about an inch (2·5 cm) thick, 352 pages with loads of colour photo's of fish. They retail at £50+ but it should be on the shelf of anyone interested in livebearers

Platies & Swordtails - An Aquarist's Handbook.
Derek & Pat Lambert.

Written by the late Derek Lambert & his mother Pat. This little paperback book is really good with loads of colour photo's of fish & biotopes along with line drawings & maps. The information is well put together, I read it in a day but it is something I refer to again & again. The book is only 124 pages but is nonetheless packed with good information. Again, another book which should be on your shelf.
I understand this book is out of print but it is well worth trying to find. Check out Amazon for second hand copies

Guppy Designer
Philip Shaddock.

Available on CD or book. It took a long time to work through the disc I had but I learned a hell of a lot from it. If you are interested in guppies you should have Phils disc. I have not seen the books yet but the disc is about the best thing I've seen on guppies.
Click the link below & order a copy.
http://www.wizardinteractive.com/guppyinfo/index.php?id=130

Freshwater fishes of Western Indonesia and Sulawesi.
Kottelat, M., A.J. Whitten, S.N. Kartikasari and S. Wirjoatmodjo, 1993.
Periplus Editions, Hong Kong. 221 p.
Page: 88, fig. 195