A veil angel has one gene for long fin (veil) and one for short fin. You would theoretically get 25% regular fin, 50% veil, and 25% super veil. However the long fin gene weakens body development especially when homozygous, so you can end up with other percentages such as 35% regular, 50% veil, and 15% super veil. You probably started out with the standard Mendelian percentages, but some of the eggs and fry did not develop, throwing off the results.