Hi! I purchased a Niger Trigger on Tuesday of this week and once I put him in my tank he disappeared. He immediately went in the rocks and I have only seen him once very briefly. Is this the usual behavior and will he ever make a presence again? I have a spiney box puffer about 1" long and an eel that is probably about 12 1/2" long. Help! I would really like to enjoy my purchase and the guy at the fish store said he wouldn't stay under the rocks.