The effect of isolation on laboratory rare minnow (Gobiocypris rarus): Growth, behavior and physiology

Laboratory fish play an important role in modern scientific research. More and more researchers have begun to pay attention to the other living environment except the physical and chemical factors of the water body, because it is not only related to animal welfare, but also related to the validity of the experimental results. Unfortunately, laboratory fish are sometimes raised alone, primarily because the impact of isolation of fish is still poorly understood. This study assessed the effects of long-term social isolation (lasting 90 days) on the growth, clustering, anxiety-like behavior, and physiological parameters (cortisol, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA)) of laboratory rare minnow. We found that isolation did not affect the growth, clustering behavior, and anxiety-like behavior of the laboratory rare minnow. However, we found a significant decrease in the levels of cortisol, DOPAC and 5-HT in isolated fish. Our results suggested that isolated environments might impact the responsive ability of rare minnows, and future researchers should thus provide appropriate living environments for them. •Rare minnow are sometimes raised in isolation, but there is no study on the effect of isolation on rare minnow.•Three months of isolation will not significantly affect the growth, shoaling and anxiety-like behavior of rare minnow.•The physiological state is significantly affected by the isolation.•Avoiding isolation can increase the repeatability of experimental results and fish welfare.