Something is wrong... I think

[Nate G]

Over the passed few weeks I have lost a couple fish. 2 weeks ago I found my flame angel dead next to a rock, today 1 of my blue chromis were acting strange and then this afternoon I found him dead. The other Chromis is acting the same way and I thought we was dead when I couldn't find him, but he reappeared and isn't doing too hot. All the other fish seem to be doing fine and are all very active. I checked my levels and everything is good. Nitrate is a little high at 20ppm, but there isn't excessive algae growth. I did a big water change yesterday and still can't get the Nitrates to 0. Anyone ever seen this? Any advise?

 

[Duke4Life]

How long setup and size? Any new additions? Do you quarintine?

 

[Nate G]

Tank is 5 months old and is 30gal. The Chromis were the very first additions. Yesterday I added an Anthias and some new corals. I haven't quarantined, but I did treat the coral before I put them in.

 

[Nate G]

Follow up: just found this in the tank. It has to be at least 12" long.

It looks like a giant worm.