Hand Held fish finder

Looking to get a fish finder for me to use in my kayak.
want something that does not require a battery , too much weight. Have seen some handheld fish finders that use AA batteries.
Any input on these or is there something better but not uses a heavy battery?
don't want spend a lot of money, just something that can show me where the fish are.
Thanks

Here is a previous thread that may help some. These SONAR units can help find cover and depth, but most on here don't refer to them as "fish finders". Just look for brush piles and then try to fish those to see if they are productive