First time grower, getting flowers but also lots of yellow leaves. Tips?

Hi. I have two plants I've been growing all summer on my back patio. One is a Trainwreck, the other it either Trainwreck or Lamb's Breath. I am not sure which is which.

The plants have grown pretty well all summer, are about 5.5 feet tall, and are starting to flower. One especially, the other only has a few little spindly guys at the nodes.

Anyways... I've had a few yellow leaves and just yanked em off all summer without too much worry. Now though, with all the flowers budding, I am seeing a ton more yellow leaves and it's making me worry.

I am using fish fertilizer and have been applying once a week.

Should I add anything else? Should I not worry about it? My regular gardening knowledge says the plants need nitrogen but I'm afraid to use any other fertilizers since I've killed cannabis plants in the past this way.

Edit: Pics https://imgur.com/a/AxTyRF3 https://imgur.com/a/tEjYJSF