I believe my octopus is going senile. He hasn't eaten anything in about 5 days nor has he come out to explore. He is rejecting shrimp, and he doesn't seem to move with the grace he once had. He moves from den to den, but that is about it. Water quality is great. I think it is probably his time to go, I've had him for more than 7 months, and he is full grown. He is a male briareus. What signs have you seen that suggest an octopus is going senile? How long might be have left?