Yea, when you're talking about 'sound,' especially underwater, there's such a fine line between, noise and vibration, more like they are one in the same
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Trying not to get as technical as possible;
Fish don't have external ears, nor 'ear canals,' but they do have internal ears, that are divided into two sections, the upper, and lower. The upper section is much like our inner-ear, and them their sense of three dimensional balance. Funny enough the upper is sub-divided into three sections, one reasonable for each of the three axises. The lower section is their hearing section. Two large plates vibrate with the noise, stimulating the hairs in the cell.
The fish's lateral line further blurs it. The lateral line receives signals, in sequence, from many cells, arranged laterally (hence the name) that are exposed directly to the water. Many fish have another set not exposed to the water These cells are similar to ears, hairs that are covered with a glob substance. The Lateral Line gives the fish a bunch of information about the stuff close around it. Like when fish are schooled closely together, or a reef fish zipping through the rocks. Similar to the sense of "distant touch" is the best way to phrase it.