Zenith ships mostly have bizarre armor types, which makes them difficult to counter properly. Usually fighters are the more capable ship, but against zenith descendants missile frigates should probably be your go-to ship since they counter most of the weird armor types (and they can't be rebounded by z mirrors).
FRD target your fighters on Zenith Shredders or Zenith Camouflagers, whichever is more bothersome at the time, and set your frigates to go after other priority targets. Mirrors are low priority unless you have ships shooting at them (or they're the only ship present), paralyzers are much more dangerous than they look, bombards are as dangerous as they look but they have artillery class armor so send bombers after them. Autobombs you'll never catch, just hope they crash into your forcefields, and keep your bombers away from them at all costs. Electric bombers are dangerous but slow, so other ships can probably be prioritized above them unless they get close to your command station.
Poll
