I woke up really early this morning (about 5:45am) and was looking at my tank (150g) when I noticed 3 of my Yellow Tangs had a large black circle in the middle of their bellies (see file below). Now I have my lunar lights on, so I'm not too sure if this is natural for Tangs at night time or if something else happened.
The only 'new' thing I have done to the tank was add a small (2 inch) spotted sweetlips to the tank yesterday (see file below), but he's been as peaceful as can be.
Any ideas?
The only 'new' thing I have done to the tank was add a small (2 inch) spotted sweetlips to the tank yesterday (see file below), but he's been as peaceful as can be.
Any ideas?