How Betta splendens finds its way

• The Siamese fighting fish Betta splendens was tested to single CS-US and spatial learning.
• B. splendens showed associative learning of a color cue and a conspecific fish.
• Fish recognized the experimental tank and showed spatial learning.
• The ability to associate arbitrary stimuli indicates B. splendens shows relational learning.

This study investigated the Siamese fighting fish Betta splendens performance in associating a stimulus with a specific cue when distractors are present. After trained to associate a specific color cue to a stimulus (conspecific) in a tank containing three colored distractors, the fish was challenged to locate the exact place where the stimulus fish was presented. With only color cues as guides, the Siamese fighting fish spent most of its time close to the color where the stimulus fish was previously presented, regardless of the distractors. However, fish trained to associate an empty place (no cues) to a stimulus fish, and then tested to localize the specific zone where the stimulus was shown, succeeded to locate the place even without any obvious cues/distractors for orientation. This study confirms that Siamese fighting fish show good conditioned learning and cannot be distracted by other stimuli. In addition, an unexpected good performance in the absence of cues may suggest the Betta’s ability to orientate by using another sensorial modalities, as magnetic orientation. Collectively, the results of this study confirm Betta as a valid and reliable model for learning and memory tests, and suggest more studies should be developed for the better understanding of the fish’s spatial orientation mechanisms.