I decided to bring the 2-gallon hexagonal acrylic tank back into use. Although we thought about shrimp or African Dwarf Frogs (Hymenochirus curtipes), we ended up going with a fighter again.
The tank has an undergravel filter and a fairly coarse gravel base, so it really isn't a good candidate for a planted tank. Nonetheless, I decided to set it up that way. That allowed me to use my plant tank for the purpose I set it up in the first place - as a source of plant material for my other tanks. I took a small Echinodorus out of the Macropodus tank, but the rest of it came from the plant tank. I took a good bit of Ceratophyllum (Hornwort), though most of it ended up in the Macropodus tank, opening up a large space in the plant tank. I also cut back the large stem of Cabomba that have reached the water level and grown across much of the tank. I pulled out a rooted Ludwigia plant and took a couple cuttings of Hygrophila difformis (Water Wisteria) and Hygrophila polysperma, which is considered one of the easiest aquarium plants (and not surprisingly, apparently it's a noxious weed).
I'm hoping the plants will do well in the new tank. I'm more interested in how that trimming will affect the plants that remain in the plant tank.