7 discoveries that prove that fish are intelligent and sensible beings

For many decades, fish and other marine animals have been left out of animal rights and welfare discussions. People used to consider them as "less of an animal", thinking that they were not intelligent or sensible enough. Despite the fact that many of them still have a terrible life in fish farms or suffer a painful death by being skinned alive, or left to die by suffocation after being taken out of the water, this notion has fortunately been changing over the last few years.

Some scientific discoveries are helping that evolution on how we see fish. "Most of the phenomena of interest to primatologists can also be found in fish, including examples of social intelligence, culture and tool use", says one study. And to prove that they deserve our compassion too, we're going to highlight some of the most impressive revelations about fish.

1. Fish can recognize human faces

Although Sinergia Animal discourages people to keep fish as pets, there is one study that is worthy of mention. Scientists from the University of Oxford in the UK and the University of Queensland in Australia who analyzed a species called archerfish found that, when they're kept as pets, they can tell a familiar human face from dozens of new faces with surprising accuracy. And you, could you tell the difference between the faces of different fish? Seems they have developed this skill much more than humans, right?

This shows a refinement in their intelligence. Humans have two eyes, a nose and a mouth, and somehow they managed to perceive subtle differences between us, just like dogs and cats do!

2. Fish can also create "tools" to hunt

A study about the capacity of fish to use tools suggests that they have been "largely underestimated in terms of their cognitive ability".

Basically, archerfish have demonstrated an impressive mental ability; they are able to think and predict where an insect is going to be, and then shoot it, even from underwater! This shows a high degree of intelligence, just like us and other mammals. Check it out:

Impressed? They are not the only one to do similar things. Tuskfish are known for opening shells by hitting them against rocks. The tuskfish turns sideways to gain leverage as it bashes the cockle against the rock. Since many of these fish do the same, scientists are beginning to wonder if this is a skill that has been taught within generations, from parents to their offspring.

3. Some of them are thoughtful parents

Speaking of parenting, scientists have found out that discus fish are as careful as other mammalian mothers. They feed their young from a mucus secreted on their surface (sounds disgusting, but their babies seem to like it!), and the nutritional and immunological content of the mucus changes as the young develop, much like mammalian milk.

"There are a lot of parallels between the discus fish's parental care and the parental care that we see in mammals and birds", says Jonathan Buckley from the University of Plymouth, UK, one of those responsible for the study.

Other fish, like South American cichlids and hoplo catfish, put their eggs in empty shells they find in the sea so that they can carry away their offspring-to-be in case of threats.

4. They have impressive learning skills...

Since fish can create "tools" to hunt or open shells, it is no wonder that research also shows that fish have impressive learning capacities, and that they use this to support a whole range of sophisticated behaviors.

Guppies, for example, showed an impressive capacity to navigate through a maze consisting of six consecutive T-junctions. After being trained for that, both the number of errors and the time to exit significantly decreased, which proves their capacity to learn. Guppies reached 68% of correct responses on the first day of training and they exceeded 80% of correct responses by the last day of training.

Some fish can even analyze how likely they are to win fights with other fish by observing and remembering potential rivals‘ previous battles!

5. ...Which is related to their good memory

Common sense says that fish have a memory of 3 seconds, but this is far from the truth. Scientists show that a simple goldfish can remember things for three months!

For instance, the crimson-spotted rainbowfish can remember escape routes to evade danger for 11 months, according to a study published by Culum Brown, of Macquarie University in Australia, who is also the assistant editor of the Journal of Fish Biology.

Many species of fish can perform complicated feats of navigation by remembering mental maps. A study published in The Royal Society Journal shows that some of them even possess a spatial map of its environment, creating in their minds representations of the order in which a series of places are spatially linked.

6. They have emotions

Even though scientists are still researching this trait, some researchers point out that, yes, fish are conscient animals and have feelings, according to their environment and to the situations they experience.

For example, zebrafishes have something called "emotional fever", which is a physical fever triggered by a stressful situation, like a fever due to sickness. Their body temperature increases 2 to 4°C when they were left in confinement during short periods. We used to think this was only presented by mammals, birds and reptiles, but surprise! Fish also have responses that directly relate to how they perceive the world around them.

7. And they feel pain

“I have argued that there is as much evidence that fish feel pain and suffering as there is for birds and mammals — and more than there is for human neonates and preterm babies". Pretty strong, huh? Who said this was none other than Victoria Braithwaite, professor of fisheries and biology at Penn State University, who wrote the book “Do Fish Feel Pain?". According to her, fish anatomy was complex enough to experience pain and discomfort.

Of course, it's not like humans experience pain. But it is still a form of pain that hurts the fish. So it means that when fish are caught in hooks or are cruelly killed, they don't struggle because of an automatic reflex. They do it because they know they're being hurt.

Their brain activity during injury is analogous to that in terrestrial vertebrates: it unwinds a cascade of electrical activity that surges toward brain regions essential for conscious sensory perceptions (such as the cerebellum, tectum, and telencephalon), not just the hindbrain and brainstem, which are responsible for reflexes and impulses.

There is still much to be discovered when it comes to fish intelligence and feelings, but a major shift has already happened: now we know we might have been wrong about these animals the entire time. Just because they don't look like us, don't live in the same environment or don't perceive stimulus the same way we do, it doesn't mean they're not worth defending.

Consider leaving seafood out of your plate, as well as other types of meat, eggs and dairy.