I have a 55gal tank with a pleco I believe to be a gibby, and a 10gal tank with an unidentified pleco. When I took down my 10gal I put the Unidentified one with the gibby. around 2 days later I found the Unidentified one dead. Then about a week later I saw this lil black thing dart around when I turned on the light. It was about as long as my finger thumb nail. 2 weeks after that I lifted a cave and this little pleco baby game out. It looks like the one that died, and acts a lot like it. My theory is that the gibby was the female that laid eggs, then the male from the 10gal tank was introduced and fertilized them. then my yoyo loaches tried to eat the eggs, possible killing the male, but one egg survived. Im still not 100% sure if its a gibby, or what the baby is. here are some pics of them. the first 3 are the gibby, and the last is the baby. Sry the pics are a lil blurry, my tank is 40years old and the glass is really etched,
http://s1004.photobucket.com/albums/af165/rjagrunt/
http://s1004.photobucket.com/albums/af165/rjagrunt/