Biweekly challenge brought attention to [tag:habitat], which not only has no wiki attached, but is only used in a few questions that are also tagged either [tag:aquarium] or [tag:terrariums], which is another problem altogether since one of those is plural and the other is not.

As it stands, of the 7 questions tagged with "habitat":

 * 2 are also tagged "aquarium" (for turtles and frogs)
 * 3 are also tagged "terrariums" (for lizards and frogs)
 * 1 is tagged both "aquarium" and "terrariums" (for substrate)
 * 1 is tagged only "habitat", but mentions "aquarium" in the title. 

In all of these entries, "habitat" is redundant.

I don't see a need for habitat and request either it be eliminated or synonym'ed.  I'd make it a synonym of "Terrariums" since "Habitat" is probably most associated with those.

This is a request (1) to eliminate / synonym habitat and (2) for plural consistency across the 2 other tags.