I've had the PBT a month longer than the Naso, so about 3 months. He was smaller when I first got him. They both are doing great. I am getting excited to get my 220 up and going so I can put them in it. Naso I got really cheap, because for some reason the petland here when they get them that small they end up dieing. I love this little guy! I also finally found Nori. They seem to like it better than the stuff I get from the petstore. I soak the nori is garlic too.