How do Fish sleep?

Researchers are investigating how fish sleep. They have found that fish do not go through the same sleep patterns as land mammals, but instead rest in a number of different ways. Some fish float in place, some wedge themselves into a secure spot in the mud or coral, and some even locate a suitable nest. These periods of "suspended animation" may perform the same restorative functions as sleep does in people. Fish ’sleep’ has an area of active research today; while there is no consensus as to what level of consciousness fish experience while they are sleeping there is strong evidence that they reduce their activity and metabolism while remaining alert to danger."