Costa Rican dwarf purple isopods (Trichoniscidae sp.) are micro-isopods that prefer tropical climates. They're the only readily-available isopod that's smaller than dwarf whites!
While they aren't exactly as bright and bold as an aubergine, their deep grey-purple hue can offer some welcomed contrast in a well-lit terrarium - especially when paired with dwarf whites.
Dwarf purples are highly prolific and can serve as self-sustaining snacks for small frogs and lizards. They're slightly more active and brave than their pale cousins, which might entice picky eaters.
These little guys are easy to culture, reproduce quickly, and do well in the normal range of parameters for typical isopods.