Sens are probably one of the slower growing polys. They shoot up pretty quick from when they are little wormlets until the hit the 5-8 mark usually around 6 months and then start to slow down. It all depends on who has them, how much food they get, environment. Its that way with them all, I saw two delz yesterday at lfs and he said supplier guessed them at around a year old they were 6 inches. I have 2 delz and one is about a year the other is around 7 months and the year old is 10" the 7 month is 8-9". I'm totally guessing at age that's how long ive had them and they both still had external gills when I got them so they were young.
Oh ok thanks for the info. Didn't realise Senegals were one of the slowest growing species of bichir. Bichir are quite rare in Australia even just a senegal costs $300 - 450$ its nuts. If your lucky you can find Ornates from time to time but they are quite rare.