Smart fish are able to recognise each other, navigate a maze, escape predators, fall in love, hunt together – let’s have a closer look what else smart fish can do.

Do fish:

Get Thirsty
Fish don’t get thirsty in the way we do but they do need water. Freshwater fish constantly draw water into their bodies due to the higher salt concentration inside their cells compared to the surrounding water. They do that through their skin and gills.

Saltwater fish lose water through their skin & gills. They need to drink seawater to balance their internal fluids and maintain proper salt levels. They do not however experience the sensation of thirst.

Sleep
Yes, Yes, fish do sleep but again, not in the same way we do. To start with they don’t have eyelids and can’t close their eyes. They also don’t lie down in a bed, but they do slow down and seek sheltered spots between rocks and crevices. Look at the parrot fish for example. They can create a mucus cocoon to cover themselves. This is to make sure predators can’t detect them, and they can get a good rest at night.

Have feelings
The myth that fish and other non-mammalian creatures like chickens and insects lack intelligence or even sentience is not true. They feel pain, are intelligent, experience fear and possibly emotion. We underestimate fish as it is hard for us to understand and recognize their feelings.

The gaping mouth and the flapping of the fins when a fish is hauled on board suggests the fish is stressed. Fish react to threatening sounds and visual cues in studies. And I have heard several stories from divers having the feeling of being recognised. For example, when they freed a manta that was entangled in a fishing net, kept returning to the rescuer.

Have memory
Here I am straight away thinking of Dory in the movie Finding Nemo.

Despite differences in brain size and form, fish have been scientifically proven to have memories lasting months, weeks and even years. They are also able to recognize and consciously avoid pain and danger, seek out reward, navigate mazes and even use tools. And like with humans, younger fish learn from older ones.

Show affection to other fish
Fish are social creatures and often seek the company of others, forming shoals or groups. While snorkeling or diving you can observe fish rubbing against each other. This may be a way of showing affection or establishing a hierarchy.

Butterfly fish and rabbit fish pair for life apparently even with members of the same sex. This suggests that these partnerships are not solely for reproduction but shows a level of care and recognition beyond simple proximity.

Some display unique body language like the powder blue surgeon fish pair swimming in circles. This behavior could be courtship or just playfulness or testing each other and defense of territory.

As mantas are widely studied, a lot more is known about them. When feeding, mantas let injured or older animals feed first, another sign that they care for each other. In another study scientists found that mantas recognise themselves in a mirror. Only a small amount of animals have passed the mirror test, mostly primates.

Fish have been around for millions of years which gave them plenty of time to evolve and develop incredible senses and abilities. During your next snorkel or dive try and get a closer look how those smart fish behave.