I have two. It's not a G. Carapo but a G. Tigre. G. Carapo doesn't have pattern on the head. You will need a tank of 24" dept. and 36" or longer in length. They are very active at night and you can have tankmates. The tankmates are on a trial and error basis. The knife will 1. attack the hell out of it, or 2. peck at it whenever they are close, or 3. leave them along completly, or 4. kill it (very rare). Most likely it will be 1 or 2. If 1, you need to remove the tankmate. If 2, they will be fine.