Smallest eel

The world's smallest known species of eel is Snyder's moray eel Anarchias leucurus, also called the fine-spotted moray. It attains a maximum length of 11.5 cm, and inhabits the Pacific Ocean, and the portion of its fin surrounding its tail dorsally and ventrally is white (hence leucurus, which translates as "white tail").

Estimating minimum lengths in eels is fraught with difficulty on account of the fact that their complex life cycle contains more than one body form. Indeed, some species pass through as many as five different stages after hatching from the egg – namely: leptocephalus, glass eel, elver, yellow eel, and silver eel (adult) – and in some species, certain of the larval stages can actually be the same length as or even longer than the adult stage. Complicating matters even further is that certain so-called eels are not true eels at all but are called eels merely because they are superficially similar in form to eels externally. Perhaps the best example of this is the famous electric eel of South America, which in reality is most closely related to the knifefishes, belonging to an entirely separate taxonomic order from the true eels.