First, what kind of cichlid is it? Species is important because there are thousands of species from all over the world.
Second, the majority of cichlids are sensitive to poor waterquality. It sounds like your fish is shimmying, where it looks like it's swimming really fast but isn't moving. Shimmy is a warning sign that the fish is extremely stressed.
The nitrites are a cause of this stress, do a 40% water change daily until the nitrites read 0.
How long has this tank been set up? What's the pH, gH, and temperature of your water? What is your matenance schedule? Feeding schedule?
For now, add one tablespoon of non-iodized salt per 10g to the water.