Nerocila acuminata is a parasitic isopod related to Cymothoa exigua, the infamous "tongue-replacer". While N. acuminata doesn't have the morbid habit of replacing the tongue of its host with itself, that certainly doesn't make it more endearing. This isopod clings onto the skin of its fish host, feeding on blood and tissue. When it detects a potential host, this parasites becomes a fish-seeking missile - it launches itself at the target fish like a guided torpedo, making precise directional and speed adjustments to ensure it lands on its target with claws outstretched . Upon contact, the isopod starts digging in, causing terrible, terrible damage to the skin of its fish. In addition to damaged tissue and blood loss, such aggravated injuries can often lead to secondary infection by bacterial infection. Compared with the "tongue-biter", this parasite is one nasty customer.
Contributed by Tommy Leung and photo by Peter Bryant.