Common Name: Sphaeromatid Isopod, Roly Poly
Scientific Name: Sphaeromatid
The Sphaeromatid Isopod are a beneficial addition to the aquarium. This isopod grows to about 1cm in size and has white to transparent coloration with potential tints or brown. They are often mistaken for a commonly known harmful parasite isopod (Cirolanid isopod) with a similar appearance. The easiest way to distinguish between the two is eye appearance of the two creatures, the bad Cirolanid will usually have large black eyes and the harmless Sphaeromatid herbivore will have smaller eyes as seen in the picture below.
Another potential way to tell the two apart is that the Sphaeromatid Isopod rolls into a ball as a defence mechanism while the Cirolanid Isopod does not show that behaviour and is generally more aggressive (and a Cirolanid is usually found attached to a fish).
Sphaeromatid Isopod in the aquarium:
Common Opinion: GOOD