I can't figure out what is wrong with my clowns.
Had them for 3 months. Only fish in the tank. Added some CUC and corals over the last 2 months. All corals QT'd and dipped multiple times, CUC wasn't QT'd. A pair of clowns was tank bred at the local LFS. I did notice female had white stringy poop as soon as I got her but was told by LFS no way they could have any parasite as they're bred in a closed system tank and all are healthy. Was told white stringy poop could be due to feeding Mysis shrimp. Switched foods and issue seemed resolved. So I didn't treat them. Everyone was doing great until 9 days ago. Clowns rapidly deteriorated within 2-3 days: stopped eating, was hanging in one spot near bottom, clamped fins and rapid breathing. Nothing external - didn't see any Ich, Velvet or Brooklynella signs. I moved them to a separate tank and decided to treat with General Cure. They improved drastically within 24 hours and by 48 hours were back to normal- eating, swimming, acting normal. Female's poop still was partially white so I treated with 3 doses to make sure. They were symptoms free for over a week. Tested main tank parameters, stable as always, salinity, temp-everything within normal. Did extra water change, replaced carbon just in case. Put them back in- did great in the evening but by the morning back to being sick with all same symptoms. I'm lost. Obviously something in that tank that makes them sick, but a decline overnight? No parasite should cause symptoms in the matter of hours. If it is some sort of toxicity then General Cure wouldn't work for that. I do have a grounding probe, can't be voltage. Inverts and corals seem fine. What am I missing? What else can it be? Please help! TIA.
Had them for 3 months. Only fish in the tank. Added some CUC and corals over the last 2 months. All corals QT'd and dipped multiple times, CUC wasn't QT'd. A pair of clowns was tank bred at the local LFS. I did notice female had white stringy poop as soon as I got her but was told by LFS no way they could have any parasite as they're bred in a closed system tank and all are healthy. Was told white stringy poop could be due to feeding Mysis shrimp. Switched foods and issue seemed resolved. So I didn't treat them. Everyone was doing great until 9 days ago. Clowns rapidly deteriorated within 2-3 days: stopped eating, was hanging in one spot near bottom, clamped fins and rapid breathing. Nothing external - didn't see any Ich, Velvet or Brooklynella signs. I moved them to a separate tank and decided to treat with General Cure. They improved drastically within 24 hours and by 48 hours were back to normal- eating, swimming, acting normal. Female's poop still was partially white so I treated with 3 doses to make sure. They were symptoms free for over a week. Tested main tank parameters, stable as always, salinity, temp-everything within normal. Did extra water change, replaced carbon just in case. Put them back in- did great in the evening but by the morning back to being sick with all same symptoms. I'm lost. Obviously something in that tank that makes them sick, but a decline overnight? No parasite should cause symptoms in the matter of hours. If it is some sort of toxicity then General Cure wouldn't work for that. I do have a grounding probe, can't be voltage. Inverts and corals seem fine. What am I missing? What else can it be? Please help! TIA.