Just a thought.....what's the male/female ratio in your tank. There should be more females than males so that no one female is being hassled to mate too much. If you have more males than females maybe the girls are being given no respite, get tired and run down.
Sounds all too familiar I'm afraid. A mate of mine was told that his claim for TV, computer etc had been approved so he threw away the damaged items. Now EQC have lost the claim and my mate has to present the items and get quotes to repair them again, which is now impossible.
No need for salt IMO but it won't hurt. I wouldn't be moving any fish either, it's just a mini-cycle, no biggie. A water change today, test again tomorrow and water change again if necessary, repeat every other day until things are back to 0.0
It may depend on where the fish is measured. Standard length (SL)measurement is taken from the tip of the snout to the caudal peduncle, excluding the tail. Total length (TL)includes the tail.