To convert pints to fluid ounces, you can use the conversion factor that 1 pint is equal to 16 fluid ounces.
So, to find out how many fluid ounces are in 8 pints, you can multiply:
\[ 8 \text{ pints} \times 16 \text{ fluid ounces per pint} = 128 \text{ fluid ounces} \]
Therefore, Fernando bought 128 fluid ounces of milk.