The less expensive models work best for shallow water fishing

The less expensive models work best for shallow water fishing. Few people would consider it a moral issue. Beyond that, most people who enjoy fishing would consider the real sin is to have this type of tech available, and to deny yourself from ever experiencing it.
For most fisherman, portable fish finders are a fantasy that has been brought to life, letting them see where the fish are hanging out.
The fishers that call the use of fish finders a form of cheating, take the position that Fishing is not just about the act of getting the fish. They even let you know when there are weeds or other things that could get in the way. But, a small portion of this group want nothing to do with fish finders, since they are purists who believe it is unfair. Some hunters may fish machine use a dog while others choose not to.That group is mostly comprised of individuals who look forward to getting to try them, and possibly get one of their own. It doesn't matter if they are fishing in a boat, from a bridge or pier, on the shore, or even doing ice fishing. The more expensive units work to depths up to 100 feet and provide more detailed readings for larger areas. Dolphins and bats have it, naturally. Another example would be hunting.

.
They way they work is with SONAR, which stands for sound navigation and ranging. The devices are hand held and they show what is the under water, & they tell you the depth. The only way there is a genuine ethical issue if is there is a competition and the rules do not allow outside help. Their screen displays are larger, in color and have better resolution. The screen displays might be difficult to read in direct sunshine. It is about the entire process that goes into it, and that using technology to find the fish for them, would take away a lot of the feeling of satisfaction that they get from fishing. These devices, emit a signal that is an electronic sound that goes into the water and bounces back, with the information.
The price range of portable fish finders is from less than a hundred dollars to more than $1000.
It is a matter of personal choice