Hey guys, my oscar has been acting very strange lately. He is the most active fish that will jump straight out of the tank whenever I put my hand remotely close.... that's how aggressive he is. But now he has been laying in the substrate and swimming kinda normal but only in the very back of the tank, whenever I walk in he becomes scared of me and hides. Now, I checked my water yesterday and there was .1ppm of ammonia and .1ppm of nitrite, I did a 50% water change and used prime to de-chlorinate the water. Today the other fish have gone completely back to normal(begging for food constantly) but my oscar is still "sulking" around the tank. Any ideas on what's going on?