I just added 3 chromis to my 70 gallon aquarium 6 days ago. They are the first fish in the tank and they were swimming around fine and eating for the first few days (they looked somewhat stressed, but it was understandable b/c they were just added). However for the last 3 days they have been hiding and not coming out to eat when I put in food. I've only put on the lights for one day and turned them off the rest of the time so they might come out. The parameters are all in check (nitrates=20 ppm
...kind of high, but that shouldn't be keeping them from eating?) It's strange how suddenly they just hide all of the time; haven't seen them come out, but I found where they hide, but I don't disturb them.
So confused and I hope I'm not overreacting! What can I do? Will they hide until they starve themselves or eventually come out again?