From Wikipedia under the Escolar page:
Effects of consumption
Like its relative the oilfish (Ruvettus pretiosus), it cannot metabolize the wax esters (Gempylotoxin) naturally found in its diet, which accumulates to give an oil content in the muscle meat of 18�¢ï¿½ï¿½21%. These wax esters may rapidly cause gastrointestinal symptoms following consumption; however, these effects are usually short lived.
The gastrointestinal symptoms, called "keriorrhea", caused by these wax esters may include oily orange diarrhea, discharge, or leakage from the rectum that may smell of mineral oil. The discharge can stain clothing and occur without warning 30 minutes to 36 hours after consuming the fish. The oil may pool in the rectum and cause frequent urges for bowel movements due to its lubricant qualities and may be accidentally discharged by the passing of gas. Symptoms may occur over a period of one or more days. Other symptoms may include stomach cramps, loose bowel movements, diarrhea, headaches, nausea, and vomiting.
To minimize the risk of symptoms, strict control of portion size is recommended as well as preparation methods that remove some of the oil. Grilling will greatly reduce the heavy fat content in the fish making it edible without ill side-effects. Portions should be no greater than 6 ounces.