The best replacement for roaches is water bugs.

The best alternatives to roaches are rated as following:
★★★★★  water bugs
★★★★  beetles
★★★  crickets
★★  ants
★★  palmetto bugs
★★  stalkers
★  immortals
★  cockroaches
★  protoss
★  zerglings
★  bed bugs
★  zealots
★  hydras
★  bedbugs
★  terran
★  american roaches
  waterbugs
  german roaches
  archons
  spiders
  water bug
  inside roaches
  bugs

Your alternative for roaches is not listed? Suggest!
Speaking about roaches, one probably shouldn't forget about boric acid.

Other search terms related to roaches and their ratings are:
★★★★★ boric acid
You have in mind a companion for roaches and it is not yet here? Propose!



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roaches
water bugs
beetles