Not sure of its identity. I think it is an O. cyanea based on location of origin (indo-pacific), base coloration, activity during the day etc. I don't know how old it is. If it is cyanea, then it will get a fair bit larger in the next several months as I believe they can get up to 500 - 600 g. Anyway, its an amazing animal full of personality and pretty much always visible. An example of personality is when I tried to feed him fresh clam flesh. I placed the food next to his tentacles and he withdrew his arm very quickly. I then placed the food under his mantle near his mouth and he grabbed it with his beak. I thought, "great he going to eat the clam". He then opened his mantle so that his mouth was towards me above the water and spit the food back at me. The clam flesh shot a few inches out of the water in the direction of my face and landed in a far corner of the tank. Mimius then sat back with a very satifsfied look on his face until I gave him some shrimp!