The Sen is now 10.5”, there is a PPolii at 11” in there as well. I use 8” as the size standard when introducing small bichirs into the big tank. The main tank has a number of old 20”+ Bichirs. It may seem counter intuitive but small bichirs are generally safer with large old mature Bichirs than they are with younger juveniles in their rapid growth phase in their first couple of years of life . not feeding live foods and a strict feeding regime also help