I went ahead and pulled out the divider between Tuna and Taco, since Tuna was tormenting Taco, and put Tuna back in a temp 2.5 gallon container. I'll pick up a 5 gallon set-up kit from Walmart this week for Tuna, if I end up not being able to find him a home.
Taco is so happy, he was wiggling inbetween all the plants and vines. I made it heavily planted, because he's such a shy little guy, I wanted him to feel safe in his enclosure. I also did the plastic bottle trick to curve the flow of the water from his filter. Now, there's hardly any current pushing into the water, it's all being directed into the side of the glass, so that's great.
It's amazing how nicely you can plant an aquarium with silk plants from the Dollar General store, LOL.