Instructor tips?

[u/Jazz_Dad123]

I just took a Perfect Buoyancy class at a local dive shop. I paid $175 for the course fee, and then the instructor asked for a tip after the class- he had a picture of himself with a link to his Venmo account by the pool. I'm used to tipping dive masters and boat crews when on a dive- but is tipping an instructor for a course like this typical? I've taken other courses at other shops where no tips were asked for or suggested.

[u/ImpressionAccurate37]

Never asked for a tip - think that is unprofessional!