The teeth of stomiiformes are often transparent and non-reflective so that prey will be unlikely to see them in the light generated by bioluminescence. Research has revealed that the transparency of the teeth of "Aristostomias scintillans" is due to nanoscale structures composed hydroxyapatite and collagen and a lack dentin tubules, however a study from a decade prior had shown the teeth of "Chauliodus sloani" (which are also transparent) have dentin tubules. The reason behind difference in presence of dentin tubules in two species of the same family (Stomiidae) has yet to be addressed. As common for deep-sea creatures, all members of Stomiiformes (except one) have photophores, whose structure is characteristic of the order. The light emitted can be more or less strong and its color can be light yellow, white, violet or red. The light coming from these fish is generally invisible to their prey. The lighting mechanism can be very simple – consisting of small gleaming points on the fish body – or very elaborate, involving lenses and refractors. The most common arrangement is one or two rows of photophores on the ventral aspect of the body. The rows run from the head down to the tip of the tail. Photophores are also present in chin barbels of the family Stomiidae. The light produced in these glandular organs is the product of an enzymatic reaction, a catylization of coelenterazine by calcium ions. During the day, Stomiiformes stay in deep waters. When the sun sets, most of them follow the dimming sunlight up to near-surface waters, which are richer in animal life such as small fishes and planktonic invertebrates. During the night, these Stomiiformes hunt and feed on such organisms, swimming back to deeper waters when the sun rises. They apparently are able to measure the intensity of the sunlight that reaches them. They will thus move to stay always in the zone where light intensity is very low, though it is not entirely dark. This daily migration is well observed in quite a few species of stomiiforms. However, it is also performed by other fishes, while some larger Stomiiformes – among them the largest predators of the deep sea – stay in their habitat all the time and feed on smaller migrating fish that return from the surface. Stomiiforms spawn generally in deep seas, but the eggs are light and float towards the ocean surface.