Complex sentence: The fish is slender, deeper than it is wide and with very small eyes that probably are not useful at the depths at which the fish lives; tripod fish are very sensitive to the vibrations of other animals in the water.
Split into simpler sentences: The fish is slender, deeper than it is wide and with very small eyes that probably are not useful at the depths at which the fish lives. Tripod fish are very sensitive to the vibrations of other animals in the water.