Colored my Gedd design. They’re more monochromatic than I’m leaning for other aliens because Gedd had no evolutionary pressure to have great color vision. Their eyes are adapted to their lifestyles and to the stresses and demands of their homeworld, such as acid rain, constant Kandrona exposure, and regular submersion in sediment-heavy pools. If they don’t have the wide-band color spectrum and high fidelity of Andalite eyes, well, Andalites stationed on that planet needed eye protection and regular flushing with saline solution to prevent damage just from being outside.

The patterns on the flat, scaly undersides of their tails are unique to each individual, like a fingerprint. Historically Yeerks on the homeworld tended to great fondness for and fascination with these patterns, though Imperial Yeerks are generally instructed that overt admiration for the features of any individual host is the first step towards host sympathy and must be curbed.

It is sometimes policy in the Yeerk Empire to amputate Gedd tails in addition to shaving their manes and any body hair that could be unhygenic, the better to anonymize hosts and reduce the likelihood of Yeerk-host collaboration. It does significantly detract from a Gedd’s ability to swim and means they can’t clean the walls and floors of filled Pools effectively, but that’s what Pool draining protocols are for.