I disagree that Flagfish are difficult to find in the US. The difficulty is that nobody seems to be familiar with these great fish. I got mine through my LFS, but he didn't even know what I was talking about. I have him the common and scientific names, and he had no trouble ordering them. I had 4 of them (2 males, 2 females in my 55 planted for about a year, then sucked one of the males up my python and it died . I threw the remaining 3 outside for the summer in a 30 gallon tub with some live plants. One female with a Betta in a separate tub, and a pair in another. I had no trouble with bugs (mosquitos in either of those tubs, and they were relatively algae free (remember I'm in Savannah, GA. with plenty of hot, sunny days). There was no filtration, and rain was the only water change (it would overflow the tubs). I ended up draining the tubs when the weather cooled off and found 5 babies in the couple's tank. They are all now indoors, doing great and growing, and the tank is basically algae free!
I like these fish because they act more like a cichlid than the other algae eaters. They will hold their own but aren't as violent as many people claim in my opinion. Of coarse every fish is different!
But my opinion for Convicts in a 29 is a standard Pleco. Their armor helps keep them alive!