Author Archives: fishetc

Boring environments create stupidity — And this applies both to fish and to humans!

A recent study found that if people want to avoid dementia as they age, they must strive for regular, active, stimulating thinking processes, in order to work-out their brains! The truth is that the human brain remains plastic and malleable throughout its life — but only if it is used regularly.

Almost immediately after reading this, I came upon another new study. This study found that fish brains, being equally plastic and malleable, adjust easily to meet its environmental needs. It also found that fish living in boring, sterile tanks devoid of all visual and other stimuli become increasingly stupid! Likewise, captive bred fish seem to be dumber than their wild counterparts, because they do not face the same adversities growing up.

I could not agree more with the statement about boring aquariums. My belief about providing proper, nature-mimicking habitats is well-known and comes across clearly in all the habitat-related articles I have written on this web-site. I do not believe, however, that captive bred fish necessarily are dumber that their counterparts. I will shortly explain why I don’t.    

 A goldfish in a bowl is a stock allegory for stupidity. As we can see, recent brain research supports this assumption. But it is not the fish that is stupid — it is the bowl that makes it that way. The bowl is void of any stimuli which the goldfish could react to with its brain.

My question is: Who put the fish in the bowl?

This situation is aggravated by the fact that pet goldfish descend from cultured stock. This means that the parents of the goldfish are given the opportunity to parent, without once having to pass the cruel intelligence tests of a real environment: they have never had to find food, or outwit predators. In short, they survived until sexual maturity without any adversity.

It is thought that the goldfish syndrome may also partly explain problems associated with fish stocking. For example, salmon cultivated on fish farms are unable to adapt to their original river habitats. Jussi Koskinen, a doctoral student from theUniversityofHelsinki’s Department of Biosciences says: “The fry most likely to survive on fish farms are those who are the first to rush to the feed dispensers. In a natural environment, such foolhardy risk-takers are usually caught by predators in no time.”

Once again: Who put the fish into the farm stock environment?

According to Koskinen, a cultured fish can also be discerned from a natural fish on the basis of their brains. The size of the brain in relation to body size grows faster in fry born of natural fish than in cultured fry. In addition, the cerebellum, which plays an important role in motor control, is larger in fry originating from wild parents and in those reared in an enriched environment.

So, there is the explanation I promised: Fish are better off when kept and reared in an enriched environment!

But there is more than that to these studies. It has also surfaced that group-living improves vision!

As we heard, the brain of a fish adjusts easily to meet its environmental needs. Researcher Abigél Gonda has compared the brain size between populations of nine-spined stickleback (Pungitius pungitius) living in the sea, and those living in small, sheltered ponds. (For your information, these are small, bony and spiky fish that raise more enthusiasm amongst scientists than amongst fishermen.)

As there is a plethora of predators, as well as varying food sources the sea, the olfactory bulbs and telencephala of the marine nine-spined stickleback grow much larger in comparison to their pond-inhabiting relatives. In test conditions, however, marine and pond sticklebacs behave in a similar manner.

It was also found that individuals who had grown up in a group developed a larger visual brain centre, while those who grew up individually developed a larger olfactory centre. Gonda explains: “Brain cells consume a great deal of energy, which is why they are allocated on a needs basis. In a group, information about your mates can be perceived visually, whereas when you are on your own, you need to resort more to your sense of smell.

It has also been found that the loss of a capacity make room in the brain for others to develop. 

For obvious ethical reasons, so scientists say, humans cannot be subjected to similar studies. (Really? Why should scientists find studies with animals ethical, but the same studies with humans not? Do we really need that kind of science, or knowledge?) 

We accept that the human brain remains plastic and malleable throughout its life. We also have come to understand what total, and even partial  isolation can do to humans. From the perspective of the brain, the accuracy of its performance is roughly equal to how many brains cells become involved in processing a given phenomenon. But it is also known that the connections between these brain cells will improve through engaging in the process.  Kai Kaila, Professor of Neurobiology explains: “Congenitally deaf people have superior peripheral vision when tested as adults. And, amazingly, people who are born blind use their visual cortex for completely different tasks, such as learning and memory.”

Most of us has also come to the conclusion that ‘cleverness’ and  ‘intelligence’ are concepts as plastic and malleable  as the brain. City dwellers rarely do as well in survival stress tests,  as people who grew up in the countryside, observing nature, and vice versa. This does not mean that either group is ‘stupid’.  They are each merely better adapted to their respective environments – which is why we speak of cities as ‘concrete jungles’. Each environment has its own set of dangers and intricacies, and that is what people adapt to. That’s all.   People are not ‘stupid’ because they cannot speak your language. They simply cannot speak your language —  just as you cannot speak theirs, I assume, or else you would have long found a way to communicate and exchange thoughts!  Let us not ever make stupid assumptions or blind judgements. We will be better people for accepting that we are really all more similar than different! 

Just so, science is a wonderful institution and can give us greater insight into our world, but only if we use it with discernment.

The point I want to make here is that instead of simply reading and blindly accepting what science tells us, we should activate our brain cells, and think things through properly. Not only do we stave off dementia by using our brains, but by understanding the findings, we can find many innovative ways to make our hobby of keeping and breeding fish much more humane, much more enjoyable and much more ethical!

After all, we are the ones who are putting the fish in the bowl —  be it the typical round goldfish bowl, or that infinitely more sophisticated square box we call our ‘aquarium’. We owe our fish perfect water conditions, beautiful, stimulating environments, and tank mates to alleviate the boredom that comes from being in isolation!

Male Cichlid Nannies… especially if they have been sneaky!

Subordinate male cichlid fish who help with the childcare for the dominant breeding pair are occasionally actually the fathers of some of the offspring they help to rear, according to new research from the University of Bristol published in the online journal PLUS ONE. This sneaky paternity increases the subordinate fish’s investment in the offspring in their care.

The highly social cichlid fish  Neolamprologus pulcher,  endemic to Lake Tanganyika, live in social groups consisting of a dominant breeding pair and between 1 and 15 subordinates of both sexes that perform brood care, territory defense and maintenance. Subordinates are often distantly related or unrelated to the dominants.

Cooperative breeding of this kind has puzzled evolutionary biologists for a long time as it is costly and often does not generate obvious fitness benefits to subordinates. In the case of N. pulcher, the main benefit for subordinates to stay in a territory of dominant breeders seems to be the protection gained against predators provided by the large group members.

Previously, it was assumed that male subordinates never achieved paternity, but the Bristol researchers suspected that, due to low relatedness between dominants and subordinates, mature male subordinates would attempt to father offspring and that achieving paternity would increase their helping behaviour.

The team, led by Dr Rick Bruintjes, tested this theory by studying groups of cichlids at Kasakalawe Point, Zambiaand found that while dominant females were the mothers of 99.7 per cent of all offspring, the dominant males only sired 88.8 per cent. Subordinate females did not participate in reproduction, but male subordinates successfully gained paternity in 27.8 per cent of all clutches.

Furthermore, subordinate males that sired offspring defended more rigorously against egg predators compared to similar males that did not sire offspring, and they also tended to stay closer to the breeding shelter.

The study shows that the cooperative behaviour of the subordinate male fish has a direct fitness benefit for them — that is, producing their own offspring — as well as such indirect benefits as safety.

Dr Bruintjes said: “This is the first evidence in a cooperatively breeding fish species that the helping effort of male subordinates may depend on obtained paternity, which stresses the need to consider direct fitness benefits in evolutionary studies of helping behaviour.”

Now, if only we could transfer that behaviour to humans….