How long can fish remember things?
Fish having a short memory may be one of the most common beliefs about fish and the most controversial. Those of us who have worked in fish stores know full well that fish remember things, and often associate certain actions, appearances, noises or people with feeding and maintenance times - like the colour of your uniform, or the removal of a tank lid.
In 2009 the myth that a fish have a memory span of 3 seconds was proven wrong, and it is now believed that their memory can last up to 5 months. Survival skills, especially when housed with aggressive tank mates, are repeated and often continuous signs of stress remain long after 3 seconds have elapsed.
Repeatable behavior and survival associated memory seems to stick but must be repeated, otherwise it is forgotten by fish after a period of time - but a time longer than 3 seconds!