Why are my fish turning pale?

Question

I have a new 30 gallon tank. I let it run on its own for a week, then put in one cobalt blue cichlid, and another a few days later. They seem to be doing good, except that aren't really blue anymore... Its like the middle of the fish is blue, and the outside of it is almost white on both fish.. Anyone know what may be going on. They look pretty healthy except for the color change, it's really noticeable.

Answer 1

When a fish becomes pale, it's usually a sign of stress. The trick is to figure out what's causing the stress.

Since this is a new tank, the first suspects would be the water quality. Running a tank for a week won't be enough time to develop the bacteria necessary to process the wastes of the fish. I would suggest testing a sample of the tank water for ammonia and nitrite, both of which are toxic in anything but minute amounts. Normally, your tank would have bacteria that convert these to nitrate, which is less toxic to your fish, but that will take 3-6 weeks in most cases: http://www.fishlore.com/NitrogenCycle.htm
http://freshaquarium.about.com/cs/disease/p/ammoniapoison.htm
http://freshaquarium.about.com/cs/disease/p/nitritepoison.htm

Also, what is the pH of your water? African cichlids generally come from areas with a higher pH and hardness, and although captive bred stock can tolerate a wider range if you pH or hardness is too low, your cobalt won't be very happy. Using a carbonate substrate or rocks meant for cichlid tanks or saltwater can raise the pH in a more stable manner than chemical additives, so this could be something to look into.

Also, are you providing sufficient caves for hiding spots? The addition of the second fish may be causing stress to both, if they're trying to establish which fish is dominant and set up territories.

As a last thought, check both fish carefully for signs of disease/parasites: http://www.klsnet.com/files/fishchart.htm

Answer 2

Try putting a dark (blue, green, or black) background on your aquarium. A light background will cause the fish to fade. Try that first and if that works, no worries.

Answer 3

This can be a lack of light
lack of calcium
The temperature may have drop quite low
or
it could be down to stress from the move into a new tank.

Answer 4

I'm guessing you added water conditioner/bacteria supplement and what not? Lack of oxygen could be one- get your water levels checked- places like PetSmart check it for free- just take a small thing of the water to them.