ALIEN – Fish-style...
As a young child in Spain, one of the main break time games in school was an organic version of marbles. Instead of the colourful glass balls, we used to flick " bicho bolas "around the ground and at each other. These bicho bolas are known in English as pill bugs, roly-polys, or woodlouse, and a biologist might recognise them as a type of terrestrial isopod. Isopods are a large group of crustaceans. They don't all roll up into "pills", nor is the whole group terrestrial. Indeed, not all are even free-living, with various species and families parasitising both vertebrates and other invertebrates. Not all parasitic isopods are obligate parasites for their whole life and, like most parasitic animals, generally each type of isopod specialises in abusing a particular host. There are entire taxa of isopods which parasitise a specific taxa of animal, with each species bound to another species. Cymothoidae is a family of fish parasites. Some of these are ectop
