BlackMoors need help

Question

 Hello,
       I have 2 BlackMoors that have started,uncharacteristically,laying on the bottom.I have a 46gln.tank with nothing but goldfish and the 2 Blackmoors but the last couple day's this has started with them. All the other fish are fine.I just did a water and filter change along with the chemical's.The BlackMoor's are alert as they will rise up and swim if I go near the tank.Also they still have their hearty appetite's.But,the laying on the bottom worrie's me as it is out of the ordinary.Any help would be deeply appreciated.Can anyone out there give me any good info. on these fish.I love them.
                                    Thank's
                                           Todd

Answer
I am not an expert on Black Moors, but I will tell you what I can.
It is probably due to poor water quality, so buy test kits and test for nitrite, ammonia, and nitrate. The nitrite and ammonia should both be 0.0, if not do regular (every 4 days) water changes of 40 percent. They may be suffering from ammonia burns, which can only be cured when the ammonia is 0.0. When the water statistics are perfect, they should be more active.
Good luck,
Kathryn