The swimming tadpole larva of has one of the simplest central nervous systems (CNSs) known, with only 177 neurons. Despite its simplicity, the CNS has a common structure with the CNS of its close chordate relatives, the vertebrates. The recent completion of a larval CNS connectome creates enormous potential for detailed understanding of chordate CNS function, yet our understanding of larval behavior is incomplete. We show here that larvae have a surprisingly rich and dynamic set of visual responses, including a looming-object escape behavior characterized by erratic circular swims, as well as negative phototaxis characterized by sustained directional swims. Making use of mutant lines, we show that these two behaviors are mediated by distinct groups of photoreceptors. The connectome predicts that these two behavioral responses should act through distinct, but overlapping, visuomotor pathways, and that the escape behavior is likely to be integrated into a broader startle behavior.