The Flying Fox and the Siamese Algae Eater are very easy to tell apart, the most obvious difference being that the Flying Fox (
Epalzeorhynchos kalopterus) has pigmented fins and the Siamese Algae Eater (generally called
Crossocheilus oblongus or
C. siamensis in this country) has transparent fins. Frankly, the flying fox is a prettier fish, but it is useless as an algae eater.
It is more difficult to distinguish the SAE from the False Siamese Algae Eater (
Garra cambodgiensis), but the latter is seldom seen in the hobby. The False SAE has a distinct white stripe above the dark lateral stripe that runs the full length of the body; in the SAE the reticulated scales extend all the way down the dorsal side of the fish to the lateral stripe. The pigmented lateral stripe in the SAE also extends into the tail; in the False SAE it does not. Here's a useful link-
https://www.tankarium.com/siamese-algae-eater/
I first tried SAE's in my tanks several years ago, and now keep groups of 4-6 individuals in all my larger (55g+) tanks. I really like them, and they completely eliminated hair algae from my tanks, My biggest concern initially was that they would get too large, but that has not been a problem as all my SAE's are ~3", even though most of them are 5+ years old. Apparently they need to be kept in ponds or really large aquaria with abundant water flow to achieve their maximum size of 6".
I am not sure that any algae eater will do the job to your standards, but SAE's are the best available, and they will certainly help. I obtained all my SAE's from PetSmart in Silverdale.