So, this all started when my coworker came into work a month ago and informed me that he had gotten an LCD screen that plays fish videos to replace his fish tank. 
He said all of the fish had died, except for two and that he had transferred them from the 30 gallon tank to a small bowl until they pass away. 
He had the tank for at least two years and, I guess, at one point, it was fully stocked but he hadn’t been replacing them as they passed. Anyway, this is how I ended up with what he called a “silver” fish and a “sucky” fish. 
I told him it sounded like he was running a fish torture chamber and he immediately asked if I wanted the fish and showed up the next morning with the 30 gallon tank, fluval 206 canister filter, food, etc. 
So began my journey into fish parenthood. I set up the tank, got the filter going, he had thrown out all the foam filters but the biomedia was still there. He also gave me all of the gravel, so I put that in. 
I started learning about the cycle and once I got new, different filters for the various levels of the canister, I started testing for just ammonia. I went to a local place and the guy there suggested that the fish were likely much more stressed in the bowl than they would be in my not quite cycled tank. 
So—I got the fish, which was a saga on its own. I then went to another fish shop where the guy got me some more comprehensive water testing stuff, but the fish are already in. 
I’ve been treating the tank with stability and doing frequent water changes with prime.
It’s finally looking like the tank is cycled according to my testing. 
Turns out, one of the fish is a rainbow fish and the other is a pleco. They’re doing great. Their names are Swim and Suck.
Now that I’ve got everything cycled, I would like to add other fish. I know that rainbows like to be in groups, but I’ve also read that they actually need more space than this tank provides. So, here’s my dilemma…do I get Swim more of her kind or do I just let her be the star of the show and get some, other, smaller fish? If so, what kind? 
What other fish should I get for this lonely duo? 
Also, what else should I do to improve Swim and Suck’s life? 


Rainbow fish friends?