Shrimp vs. fish?

I haven't been paying a lot of attention to my aquarium lately, poor fishies. But I have realized that I haven't seen my Otocinclus catfish in several days. I'd stopped feeding them algae tablets in the past couple weeks, because green algae has been proliferating in my tank, and they're supposed to eat that stuff and keep my tank clean. I wonder if maybe I starved them and my japonica shrimp ate their dead bodies? Or maybe the shrimp ate them live? The shrimp don't look quite big enough to eat my fish, but they are the biggest animals in my tank. Supposedly the shrimp eat algae too, so I guess I need not replace the Otos. They were cute though, and I feel bad if I was a contributor to their demise.