A frequented, recurring topic, that I often come across, are questions about the siamese algae eater. Often confused for other fish like flying foxes, or the larger and much more aggressive chinese algae eater, the true siamese algae eaters are fish in the family Crossocheilus.
And while that sounds all fine and dandy, a majority of these fish all look like a typical cat shark, with a single black stripe through it. That’s often where the similarities end, and the differences begin. Some of these fish that it can be easily confused with, like the chinese algae eaters (Gyrinocheilus aymonieri), get big and eat the slime coat off your fish as adults. Not good. Others, are simply look alikes, like the False siamensis (Garra cambodgiensis) or the flying fox (epalzeorhynchos kalopterus) which may eat green slime algae, but aren’t going to do much for the dreaded black beard algae.
There’s some confusion regarding the species namesake, “Crossocheilus siamensis”, and it seems this may not even be an entirely valid species at all, rather another name for Crossocheilus oblongus. Regardless, this fish supposedly has blue/yellow tint on it’s fins, and is rarely actually imported into the hobby.
Likewise, there’s the similar Crossocheilus atrilimes, this one eats java moss. Well – if you hate java moss, this is your guy, but if you like it, stay far away. The way to identify these is by the vent and anal fin – they are closer together than on other species in the family.
As you can tell – this game go could on forever, and there’s many other species in the family we could cover, as well as the unrelated look-alikes. Heck, even an oto looks vaguely like a baby one of these guys.
Crossocheilus Langei – that’s the one you want. The one with the mostly clear fins, a pair of barbels (atrilimes lacks these), and the easiest tell of all, a black butthole:
Certainly not the most pleasant topic, and hey, you can imagine how I felt chasing the fish around the tank trying to get THAT shot….but, all in the name of science right?
Crossocheilus Langei is also known as the red algae eater, more commonly referred to as the dreaded black beard algae. They are the hair algae eaters, a welcome thing in this hobby. Not many other things will go for the stuff. And this is the one you want.