[Sir Nathan XXI]

In the past I had not tried to adjust the pH in my tank at home. Tap water is around 7.4 here and my Cariba had been very hostile with eachother and their territorial disputes were frequent.

Well over the past several weeks I have been using peat to reduce pH and soften water. My pH has slowly dropped down to about 5.9 or 6.0 and I havent monitored the water hardness. Recentley I have noticed that aggression has really disappeared and territory disputes are slim to none. Temp has remained constant (well it may have gone up a degree or two) as well as and feedings are the same, basically the only things that have changed was adding peat and making it a Cariba only shoal. But from what I have read from other peoples posts and from my own assumptions I would link this behavior change mostly to the pH change.

peat was added at 1 cup per 5 gallons, water color tinting is not too noticeable

 

[RhomZilla]

I've post a thred regarding this same situation awhile back and most folks told me that PH levels didnt matter much with aggression changes.
In my old 55 gal my PH was a steady 7.1. My old Ps were skittish but were active, territorial, and aggressive towrds each other. My 125 was previously empty for a month but filled with water which lowered the PH dramatically. I've cycled the tank and occupied it with my new RBs, but the PH stays at 6.3 which they're still skittish, hudle up most of the time, and still dont go after feeders unless lights are out.

 

[Bola]

I have noticed an increase in activity but less aggression in the past when I have added black water extract. I haven't studied it systematically enough to say for sure the extract is what makes the difference, but assuming it is I don't know if the darkening of the water makes them feel more comfortable or if it would be due to the peat or other actual ingredients. The main times I notice increased aggression is simply when they are hungry and need to be fed. I don't know enough about ph to comment on what differences that might make.