Every unnecessary item were left in place when the both Xin Feng and Maeda decided to leave the shore. There were rarely animals passing by. So to not waste the food, Xin Feng ate the entire fish, since it would all be converted into a minuscule amount of Qi anyway, which means that there would be no loss or any waste of food. Such a thing was better to do than to leave it rot, hence why it didn't matter to Xin Feng if he got little to no Qi after eating the entire left-over fish.
His stomach wasn't even full, because the food that he eats are bound to turn into Qi to benefit him more, since his body is partly Qi. It was an automatic process that every cultivators in the profound or a higher realm had. That's why cultivators were able to bring an imagination into existence with their will alone, depending on the cultivation realm that they were in. Everything was partly Qi, which meant that their Qi could be converted into something as well.
