I was gonna suggest congo's too. They are native to the same region and beautiful when full grown. WAY too expensive as feeders, but it wouldn't be too expensive to restock one or two occasionally. I had a 6" sen eat an albino congo tetra once, cost about $12 to replace.
The rosies are cheaper, but i personally think the congo's are a much more interesting school to observe as the males "race" side by side all around the tank in competition!