I feed these guys a healthy pinch of spirulina flake each day. I hold the pinch under water so that it doesn’t just float down the overflow. I did this today and noticed that the tank felt cool and found that the heater was set to 75F which is a little on the cooler side for L Tang. It has been adjusted warmer.
It's warmer in the lake most time of the year but 75F is still totally fine. My Tanganyika tanks sometimes drop to 72F and I see no difference at all. Fish are even still breading.
I don’t know what I’m doing wrong. I’ve pulled two dead within a week. So, since simpler appears to be better I have swapped the Tropheus to the 6ft 90g. I think the overflow box in the 115g was creating a space for territorial disputes.
Sounds like the typical tropheus career of many people.
Its hard to tell why exactly you keep losing fish. But there are two big issues that are most likely. Too small tank and too less fish from the start on and you did too many things like changing the tank, changing te decoration, adding tank mates etc. There is a reason why many people say the number one rule for keeping tropheus is "keep your hands out of the tank".