These are optional for both Land and Aquatic Mhoats.
Aethic, more commonly known as goo, is the section of the body not covered by a mhoat's natural body plating, the normal range of this area is shown on the mhoat species page. All areas covered by the darker tone areas are where a mhoat's goo is present; the mandatory areas are the arms, ears, eyes, mouth (including teeth), and hooves. If a mhoat has a trait from the horns category, then those should always be formed from the mhoat's goo and therefore follow all color restrictions. Optional areas for goo coverage are the chest, stomach, inner thighs, and tail; when the tail is affected it will usually be fully formed of goo, and if not the shelled part should always connect to the main body except for traits like the mushroom cap tail.