My thought process on minimizing the numbers of theronts for further infestation or re infestation. Give their immunity an opportunity to fight what has attached by having less to reattach.
My understanding being that if you remove the coral to copper treat the fish then coral can't come back since rocks will absorb some of it and moving that large a volume of fish requires a sizeable vessel to house them during treatment. Kind of lesser of two evils to me.
BTW, been years but does Poly Lab Medic or other supposedly safe treatments perhaps assist in conjunction with UV to reduce further infestation? Assisted by heavier feeding to help that immune system.
I know SW ich respond differently to temperature then FW but would raising the temperature to max tolerable by corals then turning lights off for extended periods while temps elevated perhaps accelerate ich development so that they fall off and theronts can now be reduced by UV? My understanding is that corals expel their dinos only when both heat stressed and photosynthesis occurs and why coral reefs have recovered when cooling occurred right after a heat event. Outside the box and something I've posted before but seems plausible based on real world events.
Just trying to find alternatives should moving either fish or coral not pragmatic as well as learning for my own because I won't have means to treat a large tank by moving either fish or corals. QT I will try my best but we all know that's not always guaranteed.
The two options I suggested were to leave the fish in place and move the corals out and run hyposalinity, OR moving the fish out and treating them with copper - that way, no calcareous material is exposed to copper that would later on come out of solution and harm the corals.
Here is my write-up on "ich management":
Starting Ich Management during an active infection only works if the number of trophonts on the fish is below a certain number. Above that number and the trophonts themselves become stressors and the parasite gains a foothold, despite your attempts to manage it. So what is that number? It depends on too many variables - but I start to expect Ich Management to fail if the number of spots on any one fish is above 30 or so.
Here is my protocol for ich management. Please understand that I am NOT presenting this as an optimum method for controlling ich, just putting it out there for people who want to try it. Also, do not pick and choose which items you want to follow - you need to go with all guns blazing and use them all.
“Ich Management” Because many aquarists mix fish and invertebrates, they are ill-prepared to then treat for marine ich, as the two best treatments, amine-based copper or hyposalinity, cannot be used with invertebrates. A popular technique has then arisen, “ich management”. It is popular not because it works well, but because it is an easier alternative. Be forewarned, it often fails if applied during moderate infections. The reason that it exists as a technique at all is because people find themselves in situations like this and are desperate to try anything.
The basic idea is to reduce the infective propagules (tomites) of the ich parasite to the point where the fish's acquired immunity can fight the infection off. This is done through a series of techniques for stress reduction and tomite limiting. Unfortunately, the ich tomites themselves cause stress to the fish, so if the fish have more than 30 or so trophonts on them, the method often fails.
1) Install a powerful UV sterilizer on the aquarium.
2) Ensure that the fish's diet and water quality are the best you can make them.
3) Keep the water temperature close to 78 degrees F.
4) Siphon off the tank floor nightly to remove as many tomonts as possible.
5) Employ strong filtration to trap as many tomites as possible.
6) Try a proprietary "reef safe" marine ich medication. These rarely cure ich infections on their own, but some may have benefit when combined with other management methods. Avoid the herbal remedies, focus on those that contain peroxide salts. There is, however, some evidence that using peroxides with UV does not work, as the UV can break down the peroxides.
Jay
