hi,
sorry i never got back quicker, thank you for all teh replies. i have 5 of these and they live in a 240 lts tank. Other fish in the tank are guppies, kullis, few mollies and neons, and 1 grown BN.
these 5 are well over a year old now and are no bigger than 2-3 cm. My other BN grow v fast and his tenticles developed early (ish), i could see he was a BN from the start. Maybe these 5 are feel over crowded. Thank you anyway