You can discard the orders with the seabass in them. Just click on the little clipboard with an "X" on it that says "Discard" to get rid of the particular order and a new one will pop up after a short period of time.
And yes, seabass are a rare commodity - I have difficulty getting them too. I usually keep one order with a really high XP/Coin return that has seabass, until I manage to get a seabass, and discard all the rest.