This article relates the efforts made by ANPER-TOS since 1958 to fight against water pollution. It shows how some fishermen, helped by legal professionals, became the spokespersons for non-human entities which were until then excluded from representation. It discusses the problem of their political acknowledgement and management considering their singularities and the highly technical mediations they need in order to be heard. The article evokes particularly a trial concerning a pig factory farm located in Lozère, in France, and questions the materiality and the number of entities that should take into account in the making of common rural worlds.