Backyard Aquaponics
A place to discuss aquaponics

Please advise

It looks a little like Whitefly from the pics.

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Whitefly. Get yourself some lacewings to eat them. In the meantime, you can vacuum them off to reduce numbers.

I guess I'm going to say that the focus isn't quite good enough to tell. It's either whitefly like the others have stated or it's aphids and their sheds. I think it's the aphids but I can't zoom in far enough to tell for certain.

You probably have a lot more of these on the underside of the leaves.

Agree with Scotty, it's a bit hard to tell from that photo, you need to zoom in a bit closer.
Looking at it more closely, it is possible the darker blobby things are aphids, but not really possible to say without a clearer photo.

I used to use neem oil to deal with pests like whitefly and aphids and it worked well. Nowadays with the system being a bit neglected as I focus on other hobbies, I've found after a couple of years not spraying the natural predators are now sorting them out.