hi there all just a question no mater what time seems my koi are always moving around do koi ever sleep or rest.

Hi,

Nee, Koi slaap nie en kan ook nie hulle oe toemaak nie.
Hulle rus gewoonlik op die bodem van die dam of hang net in die water.

There are people who say that some species do sleep. See for instance http://www.scielo.br/pdf/bjmbr/v32n10/3339m.pdf

They do rest and go into some sort of sleep, especially if it is totally dark, but I agree with Pieter, I would not call it sleep. However, I do believe that some functions go into resting mode.

In nature, fish have predators, and if they completely shut down, they will obviously be prey very soon. Think about some fish in nature who constantly have to fight currents.