Several years ago I had a Yo Yo loach (
Botia almorhae or
Botia lohachata) in my 29g community tank and he seemed to me to scavenge anything edible, just like a cory. (Plus he would also eat snails). Yo-yo's are one of the smaller sized loaches and are actually shoaling fish so a small group of them would be much better than having a lone one like I did.
As an added bonus, unlike most other loaches (which are nocturnal, at least from what I have heard), yo-yo's seem to be quite active during the day. Or at least mine was.
As far as an algae eater, I can't recommend anything as far as fish, but I would suggest you consider nerite snails. Nerites are moderately sized (most can grow to about the size of a large gumball) and are absolutely the best algae eaters out there, even eating Green Spot Algae (GSA) which is not eaten by any other creature I know of. They are completely safe for live plants. And best of all, they cannot reproduce in fresh water (their eggs need strongly brackish/salt water to hatch) so you can add a few to a tank without worries about a snail population explosion in your tank.
Among the varieties that are native to Asia:
Red-Spotted Nerite
Horned (or Spiked) Nerite (
Clithon corona)
It's also the case that some varieties of the popular
Zebra Nerite are Asian as well, though there are at least six species that go under the common name Zebra Nerite. One or two are Asian, the others are native to the Caribbean, South America, or Africa. I believe the "big lined" version of the Zebra is the Asian one. There are also (I think) multiple species that are sometimes called Red-Spotted Nerites, and like the zebras, some may be native to other areas as well but at least one of them I know is native to Asia.
As for stocking , a usual rule of thumb for general algae control is 1 nerite per 5-10 gallons of water, so that would mean 3-6 nerites for your 120 liter tank.
Another possibility for some degree of algae control would be
Amano shrimp, though they probably couldn't keep a major algae issue in check by themselves unless you had a small army of them. Also keep in mind that a large enough fish is going to see a shrimp as a tasty little snack so this wouldn't be an option if you have big fish in the tank. (Amano shrimps get to be about 2" long, give or take.) But they are native to the biotope and are cool little creatures who will definitely help some with algae control.
Hope some of that helps.