Aquarium Fish of the World by Ivan Petrovicky and published by Hamlyn. It is an old book (published 1998) with line drawings rather than photos. Some of the information is out of date (regarding 'these fish have not been bred in captivity' or 'these are difficult to breed' for certain species now relatively commonly spawned) but I find it useful for info like temp, sexing, pH etc.
ISBN 0 600 556600 3
By the way, the marbles will work the same as a spawning grid.