I have had my blue sponge in my tank for months, with no problems, but i did alot of reading, and was very carefuly when choosing one. I waited months for one, and when my LFS randomly got a shipment of 12 in, i waited 3 weeks to see if any of them were going to survive, one did, so i have had it for aound 4-5 months, and have seen a little growth out of it. IT recently got brokedn in a rock slide, but all parts are doing great. Its in high light, med-high flow.