Discus tending to its eggs. Photo by Diskuslaich1a CC BY-SA 3.0
A recently published paper for review by Culum Brown from Macquarie University in Sydney, Australia should be of interest to cichlid hobbyist. Titled Fish intelligence, sentience and ethics, Brown proposes that fish are a lot more intelligent than what we have always assumed. After reviewing scores of research papers on fish's sensory perception, cognitive abilities and abilities to perceive pain, Brown suggests they are intelligent enough to merit the same treatment we afford other vertebrates.
Some fish are known to use tools to crush shells in order to find a meal and some species of cichlids will glue their eggs to surfaces which they can move around. Everything from long-term memory to Machiavellian intelligence to cooperative behaviour is used to get a better understanding of fish intelligence. If you would like to read more on this study, visit Springer Link. A synopsis on Brown's paper has been put together by Popular Science.