A Guyana-born poet tells of Sister Fish, who--""On a happy crick-crack morning/when wind gives leaves/a small shiver""--suddenly yearned to fly. She trades her fins for Brother Bird's wings and explores the air while he takes a turn in her river. Both are glad to return to their own places, but each has learned something: henceforth, Brother Bird can swoop like a fish, and Sister Fish occasionally leaps above the water. Agard's pleasure with a beautiful world is as evident as his pleasure in pungent languages; his deft use of cadence, repetition, and humor suits this well for sharing aloud. Kennaway, familiar from her illustrations for Hadithi's animal fables (Hot Hippo, etc.), brings out the humor and the contrasted points of view here in her imaginative, bright-toned watercolors.