Smallest moray eel

The world's smallest moray eel is Snyder's moray eel Anarchias leucurus, also known as 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").

In fact, it's possible that this species is actually a composite rather than a natural, single species, i.e., it may consist of several closely related but presently undifferentiated species. It is currently linked with A. seychellensis in what is known for convenience as the A.leucurus/seychellensis complex, but further taxonomic research is needed to distinguish how many species are in reality contained within this grouping.