cant tell clearly but it does seem to be true sae, check for 2 things 1) the black strip extends to the transparent part of the tail 2) the black strip is zigzag on the body and not a smooth line.
true sae will never perform on the same level as oto or nerite snails. They are in the same group as cherry red shrimp and should be used as secondary, not primary algae control. And just a cool fish to have.
If you want pure algae control, get nerite snails and oto. But be warned oto are so efficient your tank will be out of algae in a few weeks max then it's a lot of trouble to feed them or risk them starving to death. I ended up giving the oto to a lfs because it was just too much work to feed them after the tank is cleaned.
Now i just have nerite snails (my all time favorite algae killer), cherry red shrimps, and true sae, and the biocube remains spotless.