I would get rid of those two fish (the Chinese Algae Eater) soon. You will note that the name shaded, meaning you can click it to see that species' profile. In there it mentions their largish growth size and their nastiness. Also, as they mature they eat less and less algae and in so small a tank will likely be eating the fish, or trying to.
On the algae, if you have no live plants, I would leave it. I am assuming this is a green or red (actually looks more blackish) algae, and probably brush algae. It will occur in the presence of light and use the available nutrients. Without live plants it is actually rather useful, since it produces oxygen while utilizing some of the organic nutrients.