Male Veiltail betta, 3 gallon tank, heater, fake plants, Marimo moss ball.
I use 2 tsp Kosher salt per gallon per water change (normally 100%). I was going through a very busy, stressful time where I didn't change the water for 2 weeks, and Omelette's tail grew almost completely back. I did a water change and now his tail is down to 1/5 of its proper size.
I feel really bad because he only bites when I do water changes, so it's not like he's bored or anything, I always rearrange the decorations.
Or maybe he doesn't like redecorating?
Or maybe he doesn't like water changes in general?
I'm extremely gentle with it, but at this point I don't know what to do.