yes you can

be like..

the 3 most abundent species of fish in an ocean
the 3 most abundent species of fish in an sea
the 3 most abundent species of fish in an river
the 3 most abundent species of fish in an lake

then you can talk about how each fish survive in each body of water
then you can take about how humans effect that certain species of fish in each water body

trust me..

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R.I.P. Bodie