The best replacement for mussels is oysters.

The best alternatives to mussels are rated as following:
★★★★★  oysters
★★★★  clams
★  oysters difference
★  clams difference
★  steamers
★  muscles
★  scallops
  black mussels
  quagga mussels
  barnacles
  zebra mussels
  clams which taste better
  tahong
  oyster
  clam

Your alternative for mussels is not listed? Suggest!
Speaking about mussels, one probably shouldn't forget about white wine sauce.

Other search terms related to mussels and their ratings are:
★★★★★ white wine sauce
★★★★ white wine and garlic
★★ red sauce
★★ pernod
★ linguine
You have in mind a companion for mussels and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of mussels in all years. Click on graph for more.
mussels
oysters
clams