-> Tank has 150 watt heater (with thermostat), over the side filter
-> (will likely get an under gravel filter before setting it back up),
-> automatic feeder, timed overhead light and a dual outlet pump (will
-> feed an 18" areator stick with no problem)
You've identified one of your previous problems:  Not having an under
gravel (biological) filter.  Your "over the side" filter provides some
minimal biological filtration, but is primarily a media (gets the little
bits out of the water) filter.  Adding carbon and ammonia chips to the
over the side filter will help if changed regularly.
Get the under gravel filter!
As for fish... Get whatever looks good to you, just be sure they are
compatable.  Tetras work good together, along with Swordtails, Mollys,
and Wags.  Avoid mixing Barbs and Chiclids with any of the above
mentioned.  (Leave the goldfish for a bowl or pond).
--- Platinum Xpress/Wildcat! v1.2N
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