Myth Busting Monday: Goldfish Memory

myth busting Monday - goldfish wearing a mortar board

Happy Myth Busting Monday! Ichthyophiles, it’s your day – today we dispel a tenacious myth about one of your favourite creatures…

Myth: Goldfish have a three-second memory

Truth: Goldfish, and most other fish officially studied, have been shown to have memories extending far past the three-second barrier. Fish intelligence, cognition and sentience has been studied extensively over the years, often using the classical conditioning techniques popularised by the scientist Ivan Pavlov and his many well-trained dogs. In one type of study, fish that were fed at one end of their tank in the morning, and the other end in the evening, started to gather at the correct ends in anticipation of feeding time. This showed that they could make associations between locations, times and rewards.

If you have your own fish, this type of study is very easy to replicate (and please let us know about it if you do!). In fact, in 2008 a 15-year-old student named Rory Stokes decided to debunk the goldfish memory myth for himself. He put a red Lego block into his fish tank each day and sprinkled the food around it. After just three weeks, Rory found that the fish would start to gather around the red Lego block before he had put the food in. He also found that the fish still associated the Lego with being fed even after a week of Lego-free meals.

It’s almost certainly a good thing that fish can remember things for more than three seconds. A memory this short would be of little to no use to a living creature that had to find itself food, avoid predators, and otherwise survive from day to day.

So where did the myth come from? It’s possible that it was invented by purveyors of pet fish, to make everyone feel better about keeping fish in small uninteresting environments. It’s also possible that pet fish’s repetitive behaviours were interpreted as the fish ‘forgetting’ what it had already done, although repetitive behaviour in a captive animal usually indicates that the animal is somehow distressed. So if you do have pet fish, keep their minds active by making sure that their tank is interesting and stimulating – it’s best to consult fish-keeping experts for the best ways to do this!

P.S. If you’re someone who regularly employs the ‘memory like a goldfish’ simile to describe someone’s (or your own) poor memory, might we suggest switching to ‘memory like a sieve’? Sieves have indeed been scientifically proven to let many things through them.

P.P.S. An ichthyophile is one who loves fish. #todayilearned

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Myth Busting Monday: Breathing Trees

It’s Myth Busting Monday time! This is one that has many variations, all with a seed of truth… 

Myth: Plants breathe CO2 during the day, and oxygen during the night

Truth: OK, so this is almost right. Plants do indeed ‘breathe’ or take up carbon dioxide (CO2) when the sun is shining, because they use it to make sugars in a process called photosynthesis (‘oh, I’ve heard of that!’).

Photosynthesis converts sunlight and CO2 into sugars found in plants, and produces oxygen as a by-product. Photosynthesis is ultimately the oxygen and food source of every living being on the planet…but of course, it can only happen while the sun is shining.

Speaking of every living being on the planet, there’s another process that goes on in all their cells – it’s called cellular respiration, and it converts oxygen and sugars into energy that can be used by their cells. Carbon dioxide is a by-product of this process.

Plants are awesome because they do both these processes. During the day while they’re photosynthesising, they don’t need to take up oxygen from the atmosphere because they’re producing so much of it already. But they do need to take up oxygen at night time to complete the cellular respiration process. Luckily for us, they produce about 10 times the amount of oxygen they use themselves.

So trees are pretty great. This magnificent specimen is a Kauri pine, located outside the Cobb & Co Museum in Toowoomba. It was sadly too large to hug properly, but we gave it a nice bark-rub.

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Myth Busting Monday: Daddy Long Legs

One of our favourite things we get to do as science teachers is debunk scientific misconceptions and myths! So we hereby present to you… Myth Busting Monday! We kick off with an old, old chestnut about our spindly little friend, the Daddy Long Legs spider.

Myth: they’re actually super venomous, but luckily for us, their tiny fangs can’t penetrate our tough skin!

Truth: it’s true that Daddy Long Legs do have venom, and teeny tiny fangs (just 0.25mm). But compared with other spiders, their venom is not very potent at all. Despite this, the DLL does prey on other such famous eight-legged assassins as the Red-back Spider – usually by trapping them with strands of silk, rather than by envenomating them – but this may have caused people to misinterpret the strength of the DLL’s venom, hence the myth.

Also, in 2004 one of the actual TV Myth Busters stuck his hand in a tank of DLLs (shudder…they’re still spiders) and found that their tiny fangs actually could puncture his skin! He reported feeling a tingling sensation which soon wore off (hint: that was the venom). There are also many other anecdotal reports of DLLs biting humans, none of which led to a fatality.

Myth: Busted! 📷: Olaf Leillinger – Pholcus phalangioides (seriously though, how fun are scientific names?)

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