The study found a surprisingly long memory of an aquarium fish that could recall the location of a small piece of food encountered in 12 days. The expansion of memory capacity may give fish an advantage when food is scarce. 
In terms of animal cleverness, fish is usually much lower than chimpanzees, dolphins and mice, but it is higher than salmon. The popular view is that fish can have 30 seconds of memory. But scientists suspect that some fish are smarter than commonly thought, such as Labidochromis caeruleus, which tends to show aggression, which usually requires long-term memory. The results of the study show that fish have formed long-term memory and association capabilities that will help them accomplish more advanced tasks.