well I measured the inside of the cooler he rode home in, which was 26" when I got him home he was laying in the cooler on his side and there was about 6" left, so yeah I guessed. however when i picked him up he was in a 125 and when he turned his nose touched the front and his tail bent quite a bit so hes longer than 17" for sure, very close to 20", maybe when I move him to a huge tank ill take the time to lay him on a meas. tape and take a pic!!