Thread: fish finder problem?

we finally got out for a fish at kaikoura this weekend was a bloody great day caught a few fish but not alot of the good stuff.

i started to notice my sounder was showing "fish sign" not far off the bottom which i though might have been tarakihi schooling but after not catching anything we decided to move and try another spot. once at the next spot the same band of "fish sign" was showing on the sounder again. i played around with the gain settings to see if it would go away but no luck, so all day we were plagued by a strip of "fish sign" just above the bottom and then it started to show midwater. it was showing even when on the move.

any idea what is causing it?