She caught 8 pounds of catfish because 4 x 2 = <<4*2=8>>8
She caught 4.5 pounds of catfish because 3 x 1.5 = <<3*1.5=4.5>>4.5
She caught 7.5 pounds of bluegill because 5 x 2.5 = 12.5
She caught 20 pounds of fish because 8 + 4.5 + 12.5 = <<8+4.5+12.5=25>>25
#### 25