What is the name of this?

[sgreen]

I am not sure that they are RBTA's we have a few of them infact they have split over a dozen times and they are all fine. Like we stated earlier we had two of these white ones and they have split a few times, they are well fed and in the same system as many of the other ones that have thrived. Our water levels are all good. I do not believe these are sick or bleached.