Understanding a fish's memory

There is a common myth among non-anglers that fish have very short memories that can be measured in seconds.

If you fish, or work with fish, you will know that this is complete fiction and that fish not only have memories but are also quite quick learners.

If you have ever kept fish then you’ll know they very quickly suss out when it’s feeding time. It may be that, like dogs, they also recognise their owners!

I know that fish can recognise different people.

I’ve seen fish in aquariums ignore people passing their tanks at feeding times but when the guy who fed them came near the tank they were all up and ready to be fed.

This guy always wore the same brown coat, so presumably he was quite distinctive, but this illustrates my point that the fish didn’t simply react to the presence of people at feeding time. They knew that there were other factors involved to accurately predict when they were going to be fed.

Research carried out on fish and their memory has shown that they are capable of remembering events that occurred years in the past.

Some fish have been trained to gather around a particular spot in response to a bell and then released into the wild. A number of fish still responded to the sound and congregated at the spot a year after their release.

If catch records from fisheries are examined they often show that specific fish are caught at a particular time of year from a specific spot.

This would suggest that the fish remember that a particular food will be available at a specific spot at a specific time of year.

This all points to fish having a pretty good memory, for a creature which isn’t endowed with the biggest or most advanced of brains.

Spotting the differences

Fish are quite a diverse group of animals and, even in the UK, the variety of different lifestyles that fish have adopted means that their behaviour can be very different.

However, they all show behaviour indicating they learn and remember experiences.

Research has also shown that fish can remember being caught and will often shy away from baits and rigs that they have previously been caught on.

This is particularly true in really clear conditions when the fish are likely to get a really good look at any bait presented.

This research also shows that if the fish are well looked after during capture then they are more likely to be caught again.

This is presumably because the whole process of being caught wasn’t sufficiently upsetting for the experience to have really embedded in the memory.

It is also true that some fish are caught far more often than others which suggests that these fish are happy to be caught in return for getting extra food!

Research has shown that these fish are often at the lower end of the pecking order and is called the ‘desperado effect’.

These fish will often repeat behaviours that other fish higher up the order avoid, because it’s a way of getting more food.

Research has shown that fish not only ‘recognise’ their mates but are aware of their place in the shoal as well

Friendly fish

There is also no doubt that fish know other individuals – carp are often seen together with ‘favoured’ friends. These partnerships can last weeks or even years in some cases.

Shoaling fish have a specific place within a shoal with their ‘mates’ around them.

If you remove a fish from this shoal and put it back a short time later it will return to the same place in the shoal. If they didn’t have a memory how would they know where to go?

Some people have suggested that this actually improves shoaling behaviour because the fish get familiar with the fish around them and how they behave under certain conditions. They can predict one and others behaviour.

The larger, and presumably older fish, in a group are often the most cautious. Presumably, this is how they got to be so large, with the less cautious having been eaten at an early age!

The older fish also have a lot more experience and so will be more wary of baits in regular use.

Many fish show homing instincts and so if they are moved around a fishery they will return to their original location after being released.

River fish also move around a river to different locations during the day. They may have different spots for feeding at different times of the day, then move to another location before dusk where they presumably feel safer at night.

This indicates that the fish remember these areas and associate them with specific times and conditions which increase their chances of finding food and surviving.

Know your target

All these behaviours indicate that fish do have good memories and that they are capable of learning about their environment and surroundings in some detail.

If we take the time to learn and observe these behaviours it can only improve our watercraft and chances of catching fish.