My Garmin 9sv has been a nice upgrade over my smaller Striker 4. I got it mainly for Sidevu. I have tried adjusting the contrast and brightness up/down but everything is still pretty grainy which makes the fish blend into the background. I asked for help on a Garmin Facebook forum but few have that unit so didn’t get any helpful responses. 
 

I do see things on Sidevu like bottom structure (rocks, trees) and bait balls but the only obvious fish returns are in the black directly under the boat. Just wondering if I’m overlooking a setting that can help. I’ve tried different pallets but all still seem to not show any fish well.

Late response but searching I came across This

Read the thread and there are some useful recommendations. Not the same exact unit but same issues and helpful changes for better visuals resolution.

I have ran the 93sv UHD and in side scan the fish show up as bright suspended dots and there will be a corresponding shadow dot on the bottom. The higher in the water column they are the further away the shadow dot will be. Not sure if it is the same on the Striker Vivid 9sv but I would think it is. Check out some of the you tube videos on using side scan may help.

Best,

FM