I say it's a baby royal pleco.
you have a spare 50 gallon?im guessing you do not have mts like me(i have it BIG TIME).
that would suck for an outbreak of itch to occur :S
i do have a spare 50 gal and 10 gal tank which i could technically set up as quarantine tank.
Well when i have gotten the money and am ready to get the lights i will go with either the one freshyfresh chosen or the one roy found. If the one freshyfresh