Hello, I recently purchased a young target mandarin. I put him in my tank I've been running for over a month now, temperature is at 79, nitrates are at zero, and so is ammonia level. I have a pink zipper zoa in, and thats doing fine, very alive and colorful. I have a 30 gallon tank. I have one blue t5 light and a white one. I also have a damsel. I had him to help with the cycling. Anyways, I came home today and the mandarin was dead. He was doing fine the first couple of days, but I think he might of starved? I put in copepods, but didn't turn the filter off because I wasn't informed until afterwards that they will get sucked in. What was the reason he died?