Fish Eyes: A Book You Can Count on

``If you could truly have a wish, would you wish to be a fish?'' This question, posed at the end of Ehlert's ( Chicka Chicka Boom Boom ) latest, typically tropical-hued offering, will be answered with resounding affirmatives from captivated readers. In deepest ocean waters (midnight-blue pages) swim gaudy denizens of the deep, waiting to be enumerated by the child who ``could put on a suit of scales, add some fins and one of these tails.'' Counting has seldom been so painlessly presented, and each page incorporates a simple arithmetic lesson, as the aquatic voyager adds him- or herself to the marine groupings. Ehlert's sense of fun is surpassed here only by her sense of color: in brilliant greens, purples, oranges and pinks--to name but a few--she presents in lighthearted rhyme an amazing, appealing aquarium. For enjoyment and education, Fish Eyes can be counted on indeed. Ages 4-8. (Mar.)