Fish Bowel Water

This evening I used the following dyes for the first time with a drop of fish bowel water.

Neutral red is used to stain the nucleus and food vacuoles of protists.

Brilliant Cresyl Blue is often used to stain the nucleoli in protists.

I couldn't see anything under the microscope using the Copper Sulfate. In this photo, I didn't use any dye.

What should I look at next?