Are you hatching the baby brine yourself? The little tiny ones? If so, be sure to strain them before feeding the tank, can be lots of nitrates in the water. My mandarin won't eat the "larger" live brine that I can buy at the lfs, but we hatch our own, they look like a bunch of brown specs. Must feed them within 24 hours of when they are ready or they lose their nutrition. Very cheap to get a hatch kit. Then we turn off the filters and feed them to the tank. The mandarin goes to pecking away at the ones that land on the lr. We leave filter and skimmer off for a couple hours while all the fish eat. We leave our powerheads on, thinking that will swirl more of them onto the rocks. JME/HTH