I have a new 10 gallon tank with a 4 stripe damsel. This fish was introduced just over 24 hours ago, and was eating ferociously, up til this morning. Now i notice the damsel has a yellowish green color near his head, i am not sure if this is natural or stress because i have seen other pics of this fish with those colors and others without. I was wondering if these colors are sympomatic of high ammonia levels, i used a test and read just under 1.5, i made a partial water change and read .25 mg/l ammonia. The damsel's color appears the same. He also is no longer eating at all. Can anyone help me?