What's going ON???

Hey Everyone,
Something weird is going on here.. over the past week I've noticed my Sail fin Tang has been less active and did not eat for a couple days. He is now eating but still is a little less active.

On top of this I lost two atheis and just lost my hippo this morning.
The only thing I changed is I started feeding the tank Cyclop-eeze and I added PURA Complete in stead of a straight carbon. All my parameters seem to be in check. (nitrates a little high)

Salinity 1.022
Nitrites- 0
Nitrates-15-20
Ammonia-0
Calcium - 425
PH and Temp can be found in my signature.

Can you guys think of anything that could cause this.. Bad batch of cyclop-eeze or something?? I'm at a loss in more ways then one! :-/

 

Although nitrates are a bit up there, from what I gather fish can stand up to 40ppm in them. Ideally wanting zero of course.

Could either be a parasite or infection of some sort, or a reaction to the PURA complete, ... Or some underlining thing that we all are missing.

 

Remick J

have you added anything new recently, new coral , new rock
I recently had a battle of wits with a 2- 3 inch hairy crab (Gorrila) that had shredded my sailfins fins and accounted for one of my clown fish (I think?) so maybe you have a predator in there that is stressing out the fish when they are dormant

do you have a ground probe? stray voltage in the tank has also been said to account for behavioral pattern changes in fish and then demise

Steve