Acro eating flatworms ??
My guess is perbaps HereFishyFishy was going to have you check for acro eating flatworms. I think we picked them up about 6-8 weeks ago. We had a few frags/colonies start bleaching from the bottom up, but all water params looked just fine. Then the bleaching from the bottom gradually spread to a total of about 10 of our acros (we have over 100 frags/colonies - mostly acros - in our 155 gallon tank). Some lost flesh at a quick rate, others, like the stags, seemed to go more slowly, but always starting from the bottom up. Didn't seem to affect many of our milli's, maybe they were too 'fuzzy' with polyps - I've read that they prefer the smooth acros. The very first to show signs were a couple of our tri-color frags and our purple bali.
After a few days of being puzzled we deciced to pull out one of the worst looking frags and take it to my husband's work where he has a stereoscopic microscope -- it freaked me out to see a bunch white oval shapes wriggling around - I wanted to dash right home and do
something, anything!!
There were so many, and these were TINY, we can see red bugs easily, but we absolutely COULD NOT see these with the naked eye, and even with the magnifying glass they were extremely difficult to see even when we knew what we were looking for. These were clear and/or white and still hanging out on the bleached areas as well as at the edges of the flesh. I throught they were bigger, but the egg clusters we spotted sure looked exactly like the photos that were posted.
We pulled out all frags & colonies showing signs and treated with fluke tabs in dosage recommended on a reef central AEFW thread. (Basically 1 tab in a few gallons of salt water, dip for at least 20 minutes, then blast with powerhead and scrub areas where we'd spotted egg clusters with a soft toothbrush). We borrowed a digital microscope and have been regularly checking the previously affected frags. We redipped all frags about every 5 days for a couple more doses just in case any eggs had hatched, tho' we had checked closely with the digital microscope for eggs and removed all we saw with soft toothbrush (they were on the bleached areas, usually on the under side or in the fork of a branch).
We seem to have the upper hand, I think the key is to catch it early and repeatedly dip affected frags in case any eggs do manage to hatch. Haven't seen any additional bleaching since our repeated dips several weeks ago and no other frags with signs of infestation. Some folks claim there could be eggs on rocks that would hatch, but so far (knock on wood) we haven't seen any signs of a reinfestation. Of course, we are still keeping an eagle eye on the bases of all of our corals.
~C
