Good morning spanky...
If you keep low light plants or no plants, then lighting for your 55 G is very simple. One bulb, 6500 K
, either a 32 watt, T8 or a 40 watt, T12. These are under $10.00 each at most of the chain hardware stores.
To a small extent, lighting will affect tropical fishes' breeding behavior. But, if you have your tank lights on timers set for 12 hours on and 12 off, keeping the lighting consistent, you'll have no trouble.