Do you keep Neolamprologus pulcher, AKA the daffodil cichlid? If you keep multiples and mixed sexes of this fish together, do you pay close attention to their behavior? Ever notice a head down or a head up posture when one fish is in close proximity to another fish? If so, you are possibly witnessing social hierarchy behavioral displays. Specifically, you’re noticing submissive and dominance behavior. But which one is which?
Dominance signals are expressed with a head down display by the dominant fish. Conversely, head up displays (HUDs) are one way N. pulcher signal submission. But wait, it gets better. According to a recent study, a sub-dominant N. pulcher that displays a HUD to a dominant conspecific may delay future aggressive behavior from that same dominant fish. In other words, submissive fish who offer a HUD to a dominant fish are less likely to experience an aggressive rebuke from the dominant fish as quickly in the future, compared to a conspecific that has not offered a HUD (e.g., submission). The dominant fish “remembers” the HUD deference by the submissive fish.
This is remarkable in a couple of ways, not the least of which is that this fish has behavioral recall. There are studies that have shown fish-to-fish recognition but it’s not clear whether the recognition in this study was visual, audible, or olfactory. See the reference below to the published study.
Full Reference: Ruberto, T., Talbot, J.L., Reddon, A.R., 2020. Head up displays are a submission signal in the group-living daffodil cichlid. Behavioural Processes. doi:10.1016/j.beproc.2020.104271