My dog is healthy as a clam

In describing his pet’s lifestyle, the speaker accidentally said that his dog was healthy as a clam.  This is a nice mashup of “healthy as a horse” (very healthy) and “happy as a clam” (very happy).  The words healthy and happy are similar in sound and shape, contributing to the mental mix up.  Happy clams seem to be on people’s malaphor minds, as a prior one posted illustrates – “happy as a clam in clover”.   A big thanks to Johann Chancey for saying this one and sending it in!