Why we should take our aquatic counterparts more seriouslyThe aquatic realm holds many wonders of evolutionary ingenuity, with fish at the forefront of adapting to the challenges of their environments. A first fact, fish are paraphyletic. You might wonder what this archaic-looking word means. A paraphyletic group is one that originated from a single, common ancestor but doesn’t include all descendants from this one ancestor. This means that the ancestral species for this group is also the ancestor of one or more other groups.

Every species of fish has evolved to have traits that render it unique. The clownfish is particularly interesting in its futuristic existence in line with gender equality. Clownfish gender shift. All clownfish start their lives as males. Eventually, some become female as they mate. Groups of clownfish are always led by a female, with a male as second-in-command. When the leader of a group dies, the clownfish next in line must become a female to lead the group. Perhaps we can call the society of clownfish matriarchal. What a curiously evolved group that our human world might do well to emulate.

Some more facts, fish are the sole producers of the blue pigment in the animal kingdom. And if iridescent colours aren't cool enough, there are also psychedelic fish. Species, such as the sarpa salpa, known as ‘the fish that makes dreams’ in Arabic, are said to produce hallucinogenic effects lasting for days when consumed. Moreover, fish like the bluefin tuna and Amazonian catfish also undertake extraordinary migratory journeys that justifiably rival the more celebrated migrations of whales and birds.

Most striking of all is the revelation of fish intelligence. In recent research, animal sociologist Masanori Kohda, findings show that fish may just be one of earth’s most self-aware animals, able to recognise themselves in mirrors and photos, much like us humans.

The cleaner wrasse species, when stained with coloured dye and shown their reflection in a mirror, attempted to rub this colour off, showing they can perceive themselves. Photographs elicited aggressive reactions from these fish, when it came to any image of another fish, a response that was only absent when a fish saw itself.

Some last food for thought. Just as trees show us the ages they’ve lived in, through tree rings in their trunks, fish too hold their histories. The concentric growth patterns of fish ear bones reveal not only the age of each fish but also the nuanced interplay between climate variability and marine life. By crossdating fish otoliths, a calcium carbonate structure in the inner ear, and constructing chronologies spanning decades, we gain a window into the past.

Not only are the findings fascinating, but they help bridge the gap in understanding that our non-human counterparts are not a world apart from us. And we haven’t even yet scratched the surface.