Expert: Edward Bode - 12/6/2011

Question
Why is fish not considered "fleshmeat"?

Answer
In the Catholic Church, for penitential purposes the usual distinction is between fleshmeat [animal] and fish.  The distinction does not come from a modern scientific definition.  It is either one or the other -- meat or fish in the common estimation.
An early idea was to give up fleshmeat as a way to do penance -- to counteract fleshy and  lustful desires.  
Meat was often thought of as more tasty than fish.  
I checked a number of sources, which usually just refer to meat without a precise definition.
Thomas Aquinas[SummaTheologica, ii-ii,q. 147, a 8] in the 13th century commented that animals are those that rest and breathe on land.
So, one might say that animals usually live for a long time out of water.
Sorry not be able to more scientific.
Usually, local priests give answers to specifics.
If you wish more from me, plese feel free to write again.
Best wishes, Tom, for a blessed Christmas and a grace-filled new year.