It is said that fish only remember seven seconds, and sheep can only remember 50 faces, do you know

There's a love story that says the fish only have seven seconds of memory.

After 7 seconds, it doesn't remember the past, and everything becomes new again, and the idea is just a love story.

Goldfish actually have very long memories. Up to several years are possible.

Every time my goldfish eat bugs, I use chopsticks to pick them into the fish tank. Now, as soon as I grab the chopsticks, they all swim over.

I can't explain it for 7 seconds.

In general literature, it is 7 seconds, and depending on the brain structure of the fish and the size of the fish, some fish can memorize as much as 3 minutes.

Depending on the type of fish, fish have memories that can be as short as three days or as long as at least three months.

The catfish we usually eat belongs to a carnivorous fish. When raising catfish, fishermen feed them at regular intervals every day. In the long experience, every time the fisherman feeds the catfish, he will hit the planks and make a vibration.

Over time, as soon as you tap the plank, those catfish will rush over to feed. Even if they don't throw food for a while, they will still come by knocking on the plank. Catfish take sound as a signal to forage and can store it.

Growth and reproduction

Fish are generally dioecious, and the gonads are usually in pairs. Cartilaginous fishes are generally fertilized in vivo, ovoviviparous, viviparous or oviparous, and most bony fish are fertilized in vitro. The freshwater fish that lay eggs are sinking or floating, and the saltwater fish are floating.

The sexual maturity of fish has a lot to do with species, nutrition, water temperature, light, etc., and is regulated by gonadotropins. The fertilized eggs hatch after a certain period of time, and the larvae come out of the membrane. The life cycle of a fish is divided into embryonic stage, larval stage, immature stage and adult stage. The larval mortality rate is the highest.

The above content reference: Popular Science China - Who said that the memory of fish is only 7 seconds? Some animals have a better memory than humans, and it's okay.

Fish memory generally lasts for 1-3 months, and with training, memory will also be strengthened. Usually this is because the animal has a relatively short memory of an event, but after many contacts, let it repeat the memory, it can remember better.

Through experiments, it has been found that when the goldfish is released again after 20 seconds, it will appear frightened and dodge, and the fish will still have a tendency to avoid after a month of testing.

Fish (collectively referred to as cartilaginous fishes and bony fishes), fishes are temperate aquatic vertebrates that swim and feed by gills breathing, through the swing of the tail and trunk and the coordination of fins, and belong to the vertebrate subphylum of chordates, and generally people divide vertebrates into five categories: fish (53%), birds (18%), reptiles (12%), mammals (9%), and amphibians (8%).

According to the statistics of the late Canadian scholar Nelson in 1994, there are 24,618 species of fish in the world, accounting for more than half of the named vertebrates, and new species of fish are constantly being discovered, with an average of about 150 species per year, and more than 1,500 species should have increased in more than ten years, and there are currently about 32,100 species of named fish species in the world.