I've spent countless hours watching the 16 Orange nudis in my tank and have pulled out almost every coral checking to see if any of these are eating coral and haven't found one near any coral and all the corals are all in perfect shape, the zoas are multiplying like crazy and none have any eye lashes missing or anything. My buddy thought he would do an experiment and brought over a small piece of live rock covered in algae and we placed that and 3 Orange nudis in a pitcher of tank water and 3 days later the Rock is pretty much cleaned of algae. They look identical to lettuce nudibranchs just solid bright orange instead of green.