Sexing Angelfish is difficult at any size, but can be done with less difficulty and more accuracy than with some other Cichlids such as Discus. In Angelfish the male is often larger than the female, but this is not always the case as with some strains such as Silver and Black Angelfish I have many pairs in which both sexes are huge and exactly the same size. Also, if you do not know the history of the fish, it could end up being one of the fish is just more mature that another and you could have two males or two females at different ages and different sizes. You can sex mature breeding size Angelfish by looking at their breeding tubes which can be found under the belly of the Angelfish between the Pelvic Fins and the Anal Fin. In the males it is smaller, more pointed and slightly angled more forward. In the females the breeding tube is called Ovipositor (more generally known in both sexes as the Genital Papilla) and it is wider, larger, more blunt at the end and goes lightly backward. This takes some experience to sex accurately and is only useful in fully mature Angelfish. Some males will have a bulge or hump on the crown of the head whereas females will have a straighter forehead. This is a very inaccurate way to sex Angelfish and cannot be used reliably as there are many exceptions. Some males will have thicker lips than females. This is especially true in wild Angelfish and old strains such as silvers. The difference is very slight, is only present with mature breeder size Angelfish and cannot be used reliably. All of the sexing methods we have gone over only work well with mature Angelfish and it is not possible to accurately and consistently sex juvenile Angelfish. With all of that said, we do not sex our Angelfish to get breeding pairs. We will go over how to get breeding pairs in our next article.