The common insult ‘you’ve got the memory of the goldfish!’ is widely used. It’s used because everyone knows that goldfish have 2 second memories… but that’s not true! A team at the University of Plymouth investigated the memory span of a common, fish-tank goldfish. The team were able to teach goldfish how to perform simple tricks like swimming through a ring. The goldfish were still able to retain the skill 3 months after they had been taught the trick! Goldfish don’t have 2 second memories, it is actually much longer!
The goldfish (Carassius auratus auratus) is a fresh-water fish and was one of the first fish to be domesticated. It is also the most common domesticated fish species that is used as a pet. Goldfish can vary in size; from the very small to the very large. Over the years, I have had many of them. I’ve had tiny ones which were eaten by other fish and medium sized ones which just swam around without a care in the world. The largest one I ever had was about a foot long and committed suicide by jumping out of my garden pond! Maybe it was the case of a big fish in a small pond!
Despite their name, goldfish can come in different colours. They can be various colours: white, black, red, orange and any combination of more than one colour. Some colours and characteristics are more desirable than others and this has led to goldfish ‘breeding’. At the forefront of goldfish breeding are the Chinese. The vast majority of the global breeds of goldfish originated in China. Some have enlarged eyes, some had frilly fins and others spots and stripes.
Another common myth around goldfish is with the word ‘twit’ (or other, stronger variations of the word!). The story goes that a ‘twit’ is a pregnant goldfish. This cannot be true for one simple reason: ‘pregnant’ goldfish do not exist. Both the female and male fish release their gametes (sex cells: egg and sperm) into the surrounding water. This is a coordinate event as to maximise the chance of fertilisation. Once a sperm comes into contact with an egg, the new fertilised ova will stick to a surrounding surface and hatch within 2-3 days. This all happens outside of the fish body and therefore, there is no ‘pregnancy’ in goldfish!
————————————————————————————————————————-Whilst writing this I thought “what is the plural of ‘goldfish’? Is it goldfish or goldfishes?”. I then remembered that there is actually a difference between the use of the plural fish and fishes. In biology, ‘fishes’ is only acceptable when you are talking about multiple different species of fish. For all other times, like have multiple members of the same species, fish is the correct plural term.