Abstract Two Amazonian closely related tetras – cardinal Paracheirodon axelrodi and green neon P. simulans – were artificially acclimatized to environmental chambers mimicking future climate change scenarios (mild, moderate and extreme), using a microcosm facility. P. simulans survived (100%) to all scenarios after 30 days exposure, while P. axelrodi presented decreasing survival percentages according to environmental severity. These differences may be the reflection of distinct natural acclimatization to microhabitats between the species, which differ in thermal conditions. Survival responses might be related to differences in relative gene expression of lactate dehydrogenase (Ldh), suggesting that P. axelrodi anaerobic potential is lower or non-existent... |