This guy arrived ready to go! He was lively and all over everywhere, and he still is. I don't know if this guy's ever going to slow down. He's one healthy happy crab. I love how he uses his little mittens to pick particles out of the water to eat, and how he uses his tiny claws to pick up bits of food, or to trim off bites of algae in the few places in the aquarium where it can be found. He's just a lot of fun to watch, and I have no regrets about buying him. He's more fun than shrimp, and he is friendly to them. They are good tank mates. He's also been friendly to my fish, which are themselves good tank mates. Hillstream loaches and cryptic cory's are his bottom friends. A small school of emperor tetras are in the mid-layer as well as a trio of German Blue Rams, which aslo get along well with the crab. I also have three clown killifish at the topwater, and I honestly don't think they know he's there. They just don't come that far down from the surface. If they do know he's there, they are showing no aggression toward him, nor he toward him. I have a bubbler in the bottom of the tank to add a little extra oxygen into the water, and he seems to get great amusement out of riding the bubbles up, then gliding back down. He'll actively swim into them, then hold perfectly still as he rides the bubbles up, then he'll paddle hard to get out of them, and then hold still again until he gets to the bottom. Then it's rinse and repeat, over and over until he gets bored of it and goes off to find something else to do. Before getting this little fella I had no clue that a crab could have such a big personality, or that they were capable of play, but he plays a lot. And not just in the bubbles. If all Pom Pom Crabs are like this guy, then you'll be in for a treat if you get one.