Question The Hawthorn fish tank

I was wondering if in the Gen2 setting the school removed Foob's tank or not.

Removed it? Probably not. It was a considerable investment building it in the first place, and there would be always other aquatically mutated 'Thornies who could make good use of it. At the very least, it's an indoor swimming pool.

Hmm, what did they do with Fubar before the Seaworld style tank was built? Keep him in the swimming pool? Or was the pool a Precog addition to the original reno?

One expects that a small tank was improvised in a hurry (the Whateley tech staff is good at that), and later, as it was determined that Louis' condition was permanent, there was a lot of discussion on a more long-term housing solution for him. Probably there was an intermediate stage with a smaller tank when it wasn't clear yet that Louis would become a permanent Whateley resident. In fact, I think there was a mention somewhere of a temporary tank Louis could be transferred to so large maintenance work can be performed in the big tank -- that's probably Louis' "old" tank.

He was probably just chilling out in Carson's bathtub...