“On their arrival in Capernaum, the collectors of the Temple tax came to Peter and asked him, “Doesn’t your teacher pay the Temple tax?” “Yes, he does,” Peter replied. Then he went into the house.
But before he had a chance to speak, Jesus asked him, “What do you think, Peter? Do kings tax their own people or the people they have conquered?”
“They tax the people they have conquered,” Peter replied.
“Well, then,” Jesus said, “the citizens are free! However, we don’t want to offend them, so go down to the lake and throw in a line. Open the mouth of the first fish you catch, and you will find a large silver coin. Take it and pay the tax for both of us.” – Matthew 17:24-27
The name “Saint Peter’s Fish” comes from the above story in the Gospel of Matthew. Peter caught a fish that had a coin in its mouth, just as Jesus predicted, and paid the Temple tax with it.
Although the passage does not name the type of fish Peter caught, it was very likely a Tilapia. Tilapia were one of the three main types of fish caught in Biblical times from the Sea of Galilee. Tilapia breeds easy and has a mild taste – not fishy. In factory fish farms today, they harvest large numbers of Tilapia which happily eats pellets made largely of corn and soy and gains weight rapidly.
At the time the gospel events took place, Tilapia were called musht, or later called “St. Peter’s fish”. A common Bible story says Jesus fed the 5,000 people with five loaves and two fish, which scholars surmise were tilapia.
– Luis Josephus