Deep background

Deep background. Some books, even though they are not directly about fish and fish-keeping, spark my imagination about aquaria. They would come under the heading of "deep background" I guess. (Just about all of these books are out in paperback.)
 
A fresh way to see that our aquaria's dynamic balance of interrelated cycles (including the nitrogen cycle) is a genuine microcosm, not just some sort of sentimental poetic metaphor, is James Lovelock, The Ages of Gaia: a biography of our living earth, 1988. If you understand that life has transformed the physical planet in an interconnected web, but you're not quite prepared to think of the planetary biosphere as if it were one giant single cell, perhaps you could think of Earth as a big aquarium! At last this book is  out in paperback .
 
Moving in to focus a little closer, T.C. Whitmore, An Introduction to Tropical Rain Forests (2nd edition) Oxford U. 1998 gives you the ecological framework of the planet's three great rain forest systems, with some introduction to ecologists' special mind-set and jargon. You'll find that freshwater fishes are ignored, save for the fruit- and seed-eating habits of some Neotropical fishes, but you won't be disappointed. The Amazon basin contains the largest still-unfragmented tropical system.
 
Adrian Forsyth and Ken Miyata's modern classic, Tropical Nature: life and death in the rain forests of Central and South America, 1984, lays out a picture of the cycles and systems of which freshwaters are a part, though again they never directly discuss aquatic life in the rain forest!
 
South East Asia is another tropical region that figures in my fish dreams. Penny van Oosterzee, Where Worlds Collide: the Wallace Line, 1997, gave me a picture of the geological assembling of the land masses that make up Indonesia, and put meaning into the seeming arbitrary distribution of freshwater fishes there.
 
Lynn Margulis and Dorion Sagan, Microcosmos: four billion years of microbial evolution, 1986 (available in paperback), opened my eyes to bacterial metabolisms and survival strategies and to the role bacteria have played in the shaping of the world and the evolutionary history of the cell.
 
John Postgate's primer, Microbes and Man, in its fourth edition, 2000, very meticulously revised (also available in paperback), discusses microbes in society, in industrial production, in nutrition and disease, in decay processes and pollution management, much of which relates to wastewater management and thus to aquarium cycles, and he touches on bacteria in evolution, too.
 
Then, in Postgate's other famous book for the lay reader, The Outer Reaches of Life, Cambridge U. Press paperback, 1994, he discusses bacterial metabolisms in extreme environments: haline, acidic, hot and cold. He discusses aerobic and anaerobic bacteria, nitrification and de-nitrification, and plenty more stuff that quite directly concerns fishkeeping, though aquaria don't enter his story. It's all beautifully and clearly written for an average reader like me, no better prepped than most aquarists are. And it's all illuminating for fish-keeping.
 
If you like Postgate's books, you'll get a lot out of two others: David B. Dusenbery, Life at Small Scale; the behavior of microbes, which was no. 61 in the Scientific American Library Series... and Dorion Sagan, A Garden of Microbial Delights: a Practical Guide to the Subvisible World, 1988.
 
A more direct fish background is offered by Peter B. Moyle, Fish: an enthusiast's guide, U. Cal. Press, 1993. Moyle is the co-author of one of the main college-level ichthyology textbooks, but here he's mining an accessible vein, giving you the best short introduction to fish structure, fish behavior, and ecology. This is the book to find when you want more depth than the aquarium guides.
 
I'm still relying a lot on N.B. Marshall, The Life of Fishes, in the World Natural History series, 1966, though it's beginning to be a little dated. More up-to-date, I know, is Peter Moyle and J.J. Cech Jr, Fishes: An Introduction to Ichthyology, 1996.
 
Stephan Reebs, Fish Behavior in the Aquarium and in the Wild, 2001, explores the senses and reactions of fishes and describes the ingenious techniques researchers devise to test them.
 
George Barlow, Cichlid Fishes: Nature's Grand Experiment in Evolution, 2002 is a classic written for the curious layman rather than for the cichlid hobbyist, who is already well served in specialized cichlid books from the aquarium point-of-view. Barlow is a biologist and teacher who has inspired a generation of ichthyologists at Berkeley. He discusses cichlid jaws and sex and mating strategies and explosive speciation in the African lakes. It's great stuff, and it will bring you right up to date on issues that apply to many fishes besides cichlids.