I came home this eve after two weeks alive and my green mandarin goby/dragonet was laying on the bottom with slime , he had to have died somewhere after 6 am this morning. I inspected him well, he did not have any signs of being in a fight ,or disease, I do however have a 4 in long blue/pink spotted goby who spends his time on the middle of the tank in the backside hidden in the sand.under rocks. the temp is 86.6 deg, the ph =8.4 and my salinity runs 1.026/1.027 , alk is dhk = 11 , zero nitrates/ammonia ?? he was eating /picking pods off the back wall of my 160 display tank for 2 weeks now. he was fat and healthy. so what happened?? Totally confused and SICK!! I hate losing my fish , cheap or Expensive they are my babies ?? tank is 1-1/2 years old. All other fish are fine. I have a Pacific sailfish tang, a Blonde Naso tang, 2 pair of clowns= 2 mated True percs/ 2 mated ocellaris/ 1 banghai Cardinal/ 1= Flame Hawk-fish/ 1 Blue reef Chromis/ a Xmas Wrasse/ and yellow Coris Wrasse / 12 total. My tank is 5ft lg 22 tall, 30 in wide, I have a 75 gal sump/75 gal fuge. Total of 310 gallons. :sad: