“…To quantify the degree of abnormality in Hgexposed Fundulus heteroclitus, Weis et al (1982) developed a craniofacial index (CFI) in which each embryo's convergence of the eyes was graded on a scale of 0-6, where: 0 = normal, 1 = slight convergence, 2 = greater convergence to touching, 3 = synophthalmia, 4 = fusion into one median eye with two lenses, 5 = cyclopia and 6 = anencephalia. In zinc-exposed Pimephales promelas embryos, Dawson et al (1988) reported incomplete gut coiling, skeletal kinking, edema in the dorsal fin, fin blistering, edema around the eyes, improperly formed mouth, head and eye, and brain reduced in size. Copper and cadmium caused a reduction of pigmentation, and chromium caused deformation of the notochord of Clarias gariepinus (Nguyen and Janssen 2002).…”