When i first got back into the hobby i was sold 5 cigar sharks for my tank and told they only get to around 5 inches
Within 3 months the biggest one was 11inches,luckily for me i managed to rehome them,they were managing to eat fish as big as full grown gouramis in one go
Isn't it also called the cookie cutter shark? If so, be very very carefull. They are notorius for easily eating large chunks of flesh. If it isn't also called the cookie cutter, please ignore this post.