YOU SAID:

I have one cat named panther who is a pretty fat and black

INTO JAPANESE

かなり太くて黒い猫、パンサーという名前の猫を1匹飼っています

BACK INTO ENGLISH

I have a very thick black cat, a cat named Panther

INTO JAPANESE

私は非常に太い黒い猫、パンサーという名前の猫を飼っています

BACK INTO ENGLISH

I have a very thick black cat, a cat named Panther