MM, u mean live brine shrimp or frozen? Ur fish must be big enough to eat frozen foods, I grind frozen foods for Lori.
I just did a 25% WC(its been 2 weeks) and inserted a carbon, when I noticed black particles all over my tank, particularly on the bottom and on the surfaces -- I realized that it's a magnet which suddenly started disentegrating!!! OO How hazardous do u thing these metal particles would be for my fish, I will do another WC tomorrow, since the integration started right after this WC(i had this magnet to weight down one of the plastic pipes...i had it in there for these past 2 weeks and didnt notice anything)