Please help me with an explanation I will mark brainliest!

Answer:
The mean of the data is 3 fish.
Step-by-step explanation:
To find the mean, you add all of the data together and you divide it by the number of numbers.
So, in this situation, you would first add 0+3+6 and get 9.
Then, to find the mean, you would divide 9 by 3 and get 3.