Fish resilience can be understood as the capacity of fish to successfully respond to a challenge so that they are able to function and flourish in much the same way as they did prior to the occurrence of the challenge. Resilience is a function not only of individual fish, but also of a whole fish population. Enhancing the resilience of fish requires both adapting the robustness of the animals and adapting the (production) environment to the specific needs of the fish. Rather than a mere biological capacity of fish, resilience also comes with ethical questions. These questions occur at four levels. First, in practice resilience often comes with a “rhetoric” of optimalization. The view that aquaculture that strives for resilient fish is good for both fish welfare and production is inherently normative. It assumes a ‘win–win situation’, but thereby makes certain normative assumptions. Second, especially when the win–win situation is not achievable, resilience means making trade‐offs between preferred responses to challenges from the perspective of individual animals and groups or between individual housing and larger aquaculture systems. Third, the discussions on resilience and fish demonstrate the need to move beyond an animal welfare framework when discussing the treatment of fish in aquaculture. Recently, animal ethics has seen a turn towards centering animals' own agency. This means that we should not only focus on improving animal welfare, but also on asking what the animals themselves want and how they can be given more control over their situation. This may also impact the definition of resilience and how it is made operational. Finally, the use of the concept of resilience may reveal a certain moral outlook with regard to fish. On the one hand, resilience is portrayed as a positive characteristic of animals that enables improvement of the quality of life of fish. At the same time, it raises the question of how far we should stretch the “manufacturability” of fish. When we physically adapt animals so that they can cope with difficult circumstances we may be stretching moral boundaries. For example, this raises the objection that we are instrumentalizing animals. In this article, we reflect on these types of ethical issues and aim to show that the ethical dimensions of resilience need to be taken into account by professionals in aquaculture in order to make resilience operational and to contribute to a responsible interaction with fish in aquaculture.