©L. Brian Stauffer

The colourful anemonefish, Amphiprion ocellaris, may be better known to many of us as ‘Nemo’ from the well-loved Disney film. However, it seems that real life does sometimes mirror the movies in the latest research on parental care in this species.

DeAngelis et al. looked at the effect of the hormones isotocin (IT) and arginine vasotocin (AVT) on male parental care. In contrast to most species, male anemonefish are the main parental caregivers, expending vast efforts to guard their eggs.

Isotocin (a homologue of oxytocin in mammals) was found to play a critical role in paternal care. High levels increased male parental behaviours (such as nips, fanning the eggs, and the proportion of time in the nest) whereas introducing an IT agonist decreased these behaviours, but did not affect aggression. Blocking AVT, on the other hand, had the opposite effect, increasing parental behaviours. High levels of AVT have previously been implicated in aggressive behaviours in these fish.

The researchers hypothesise that blocking AVT signalling results in the fish reducing the amount of time spent on vigilance and nest defence, allowing more effort to be directed towards parental care.

Read the full article in Hormones & Behavior 90 113–119