I have an Eclipse 12 system that I set up a couple of months ago. I have aragonite sand (2mm) and 9lbs of fiji live rock, halimedea. All water params normal, salinity normal. Use dechlorinated water to set up - had diatom bloom, did water changes with distilled water- problem rectified,
RO filter on order. Added 1 scarlet crab & 3 Astrea snails all OK, params normal. Added Blood Red Fire Shrimp died after 8 hours

, ordered Bluegreen Chromis (mail order) placed in tank, was pale in color- trauma from shipping? The fish darted all over the tank, tired out , started swimming vertically, rested on sand surface - died

. Checked all params again- all normal, salinity normal. Should I check
O2? I have good flow, lots of tiny bubbles. I know I have a small tank, don't want to overload. Any suggestions on what I might be doing wrong- and help would be great.