My teacher has a 40gal. with a piccaso trigger. And with some of the kids in my grade this is not a good idea.The fish is being constantly tormented by the magnetic cleaner and some just pound on the glass sending the trigger to hide in the coral. just last week one of the not so bright kids pulled off the outer part of the magnetic cleaner sending the inner piece to the top of the tank. Well this kid deciced to pick it out and sure enough the curious trigger came up and bit the kid's finger well I thought it was kind've funny but the kid thought otherwise.