In the wild, the Mata Mata appears to be a nocturnal feeder and is known to eat a large variety of foods such as fish, freshwater invertebrates, and even small mammals and birds that venture in the water. In captivity they require live fish of the appropriate size for the turtles, so they can swallow the fish whole. Bait fish, like minnows are commonly used. The fish should be kept in a separate tank before feeding them to the turtles to ensure that they don't have any diseases and to get rid of all the drugs and chemicals in the fish's system. There appears to be a lot of debate concerning feeding of goldfish.
Some caregivers state that they can cause injury to the turtle with their fins.
Lastly most goldfish are raised in environments requiring copper sulfate in the water. Many keepers of Mata Matas believe that increased exposure to the copper sulfate will become toxic. Other hobbyists, however, have fed frozen goldfish with no problems. Relatively Difficult The Mata Mata has not been bred often in captivity. In the wild the Mata Mata will begin to nest between October and November.