Exactly one week ago I changed the gravel substrate in my tank with a bag of ecocomplete substrate. The first two days after adding the new substrate my black moor was acting his normal self swimming around the tank and picking at the substrate. Although for the next three days he stopped eating all together and would only swim in one spot. On that second day of the fish not eating I changed out about half of the water. The next day I bought a water test kit to see if there was something off with the hardness, pH, nitrates, or nitrates. Nothing stood out of the ordinary as the water was fairly hard which is normal for my area and I’ve kept perfectly healthy fish in this water before. The pH was between 7.2 and 7.5 and both nitrates and nitrites were at 0. After that I did a water change to get all the food out of the tank that the fish didn’t eat. I have just the one black moor in this aquarium. Then on Wednesday I tried feeding the fish some blanched broccoli but it has gone untouched to this day, one week after adding the substrate. My only theory is that changing the substrate has stressed him out and that it will take longer for him to adjust than I had thought. Although, his behavior was normal for the first two days and now he acts almost zombie like staying in one spot, facing one direction and not eating. His color is normal and all his fins look great and he has the ability to swim around perfectly fine, but doesn’t do so. I don’t understand how the ecocomplete would cause this as it’s made for stocked aquariums but i will remove it if I must. It should also be noted that when the fish does poop, it is often white, sometimes being normal length and stringy or normal length and thick.