Are you familiar with the market price of Berghia? Its been $25 each for them when they get to 12mm in size. Sale price has been $15 to 18 each. BUT we pack them up for less at $45/per trio and they have to be starting to lay eggs. (Special Discounts - Read all the way to the end!) That means they are at least 6 weeks old. They work best in colonies, so thats part of the reason for the 3 paks. The more aiptasia and larger tanks, the more Berghia. They are very, very effective! How heavy is your aiptasia problem? Large Berghia verrucicornis (Possible confusion with Aeolidiella stephanieae or vs) Nudibranchs 2 trio paks would probably be best (or more) if there are a lot of the aiptasia. Colonies work best. I used 3 in my refugium and 8 in my 125. My tank was really bad - little aiptasia got under the coral and started killing it. I don't even have any aiptasia left in the sump now either! And no effort on my part since I put the Berghia in there. I was at the point I would have paid hundreds for such relief! Reminds me of that ad that ends in "priceless". Berghia are the best investment in pest control I ever made and have no side effects. They take a little while to establish the colony and start to work but little by little your aiptasia worries will be over. (You can not expect these to fare well if you have any peppermint shrimp or camel shrimp in there.) Photograph is magnified approximately 2 to 3 times for easier viewing. Look real close at the hole in the center of the rock. There are little aiptasia down in the holes and our nudibranches go in to get them out for good. A 100% reef safe natural aiptasia predator, all natural solution for aiptasia anemone pests! Unique to our nudibranch solution over other predators and methods; No dying remnants are left behind to foul the holes in the rocks or regrow and the aiptasia in these holes are completely removed once and for all!