FAA creating pressure in jars

Hey there, I made my first batch of FAA (over 5.5 months) this winter. It smells slightly fishy, but in a candied salmon kind of way (not bad). I strained it last week and put it into 1L glass jars with sealers, and I've noticed that there has been pressure build up if the jars are sealed tight. The FAA was somewhat thick when straining. I have LAB I was considering adding to the jars, but perhaps more brown sugar is the best bet to stop the activity for storage? Any advice?   Thanks!