I have a 30 g long tank that has 1-2 wpg light and a yeast bottle that
feeds into the macerator of the waterfall filter. I have one large angel and
one ditch minnow. See image under same subject at
alt.binaries.pictures.gardens (if it ever shows up).

I also have about 30 small plants that, while they are growing, they are
growing slowly. By that I mean one leaf every 6-12 months. I suspect it may
be a combination of lights and temp. My A/C keeps the tank at about 78f.

Do I need a heater?

--
Sam-I-Am
Don't judge each day by the harvest you reap, but by the seeds you
plant. -Robert Louis Stevenson