I agree with Greg ... Screenshots from the unit are easier to interpret in the forum here than pix from a phone or camera ...
Your images do show a few fish ... With practice you will be able to start picking them out ...
Fish echoes do not usually show as "streaks" ... but show more as white dots elongated just a tad ...
Sometimes the shadow of the fish is noticed 1st ... Then the shadow leads the eyes to the white dot echo that created that shadow ...
I would suggest keeping the Contrast at about 8-10 To make the image not as "grainy" ...
Then use the SI Sensitivity setting to adjust the brightness/darkness of the image to your eye's preference ...
Have you thought about upgrading to the XHS 9 HDSI 180 T Hi-Def SI xducer to add the 800kHz capability of the 899 ... ??
Rickie