I have a 150 gallon tank that has been established for over three months now, with 24 hybrid bluegill. I had to reduce the temp by 2° over several days. From 75 to 73 degrees F. I did this because I felt my lettuce was bolting, as It was growing tall, but no flowering. Anyways, my gills have slowed down their eating, and some seem to have stopped all together. There is plenty of airation. PH is fine. Ammonia, and Nitrite are zero, but nitrates are at, or above 160ppm, which is where its been for two months. There does seem to be some territorial disputes among the larger ones however, but not sure thats the problem. I should just turn the temp back to 75°, but I don't believe thats the issue, just coincidence. I did supplement their food with premium talapia grouth pellets, along with their normal premium fingerling pellets from The AP Source. Anybody have any input on this phenomenom?
another note.. i read an osu study (sorry it was a while ago) that indicated bluegill fingerlings will be stressing if nitrates are at i think 400 or above.. you might want to do another partial water change to get your system at least measurable..
don't worry about "hard water" in your system in the early stages.. it will be fine and is actually better for the cycling proces