Really sorry to say this, but I don't think a yoyo can be kept in a 2'-long tank or should be kept alone.
Mine grew up (from 1") in a 29g, which is 2.5', and I saw them getting uncomfortable once they got to about 3"...this is when I moved them to a 6' tank; the ability to run the entire length of the tank made them much happier. I'm not saying that yoyo's really need 6'...but 4' they do, and anything less than 3' will not work once they grow. And they grow pretty fast, so if you don't see a proper tank on the horizon, you cannot accommodate them.
If you like loaches, switch to a smaller species.