At New York University, a prominent group of international academics have signed The New York Declaration of Animal Consciousness, which states that “empirical evidence indicates at least a realistic possibility of conscious experience in all vertebrates … including … fishes”.
It defines consciousness in terms of “subjective experiences”  which include “pleasure, pain, hope, or fear” and cites experiments with cleaner wrasse that suggest a degree of self-awareness and with zebra fish that show signs of curiosity.
The study of animal sentience includes academics working within neuroscience, veterinary science, evolutionary biology, social science and the humanities. 
The Declaration states that it “makes no specific policy recommendations, and the signatories have a wide range of views on moral, legal, and political issues.” But in background information, its authors add, “Policymakers should take reasonable steps to mitigate welfare risks for all vertebrates and many invertebrates as researchers seek to advance our understanding of them.”