Need Help - Book illustrating fictional life on all planets in our solar system

[del420]

I read this book that portrayed the various fictional alien life that lived on the (then) nine planets of the Solar system. Flying pterodactyl-like predators that fed upon the flesh of floating blimp-like creatures on Jupiter. Jumping methane-eaters on Neptune and the like presented in a psudo-scientific style explaining their diets and environments. The book had beautiful painted artwork, not illustrations with line drawings. I cannot remember author or title but I do know the book is at least 15 years old. I believe it may appear under a children's book category although the writing was solid and would appeal to anyone interested in Science Fiction.

I've been looking for this book/pictures for many years now.. PLEASE HELP