Do goldfish sleep?

Question
I have had a few common goldfish during my life, each living about five years.  I have never, ever seen any of my fish "resting."  Each fish has lived alone in a large tank in a quiet room with regular "dark" and "light" times.  My current fish is in constant motion, swimming ceaselessly from one end of its tank to the other.  I have monitored the behavior of my fish during all hours and it never stops swimming, never rests on the bottom, or even floats suspended in the tank.  There are decorative caves and crevaces it can go inside but it does so only while actively searching for food.  Even in the darkness at night the fish is swimming and active.  I've read that goldfish sleep but none of mine have ever been spotted resting... could you tell me whether they might be sleeping while moving or perhaps sleeping only for minutes at a time?  Thank you.

Answer
Hi Bonnie,
Thanx for your question.  Goldfish do rest.  Sleeping is a concept that is different for the various species of life in our world.  Many species do not require the type of sleep that humans require.  Fish do REST but, if you are wondering if they run into a cave and float aimlessly while they sleep?  No, fish do not sleep.  They will slow down their metabolism and REST in a safe corner of their world.  Also, fish activity becomes slower in the evening and when water temperatures drop when they are in safe places.  I hope this helps.
Tom