unusual parasite...

[kittyhazelton]

So, this has been circulating around my fish for the last few months. It only seems to affect 1 fish at a time, and the symptom the fish exhibit are loss of appetite, itching on rocks, & fanning their fins at the surface of the water.
I noticed my blue-streak damsel doing this so I pulled him out and did a freshwater dip. These weird little blob creatures die pretty much instantly when being introduced in the freshwater & flake off the fish. When they're alive on the fish they are clear & slimy looking, and move almost like leaches... they are TINY, ike . in fact, this picture is the LARGEST one I've ever seen, this is in a shot glass & approximately 1/4th of a centimeter in length. The turn white when introduced to freshwater.
So far, of the fish that had gotten it, the first one I didn't notice them until it was too late & it perished, the undulated trigger got it, freshwater dip removed them & cleared up instantly he's returned to healthy behavior, then now just my blue streak damsel.
Any idea what this is? And suggestions for permanent eradication from my tank would be great. I was thinking that since freshwater dip kills it maybe reducing the salinity in the tank my help.

 

[Kevin8888]

Hmmm looks like a flat worm of some sort... specifically Monogenean Parasites known as flukes/flatworms, basically if they are in your system you need to treat with copper at 0.2 mg/L active copper ion for up to three weeks. Keeping in mind that a number of fish and all inverts/corals dont tollerate copper well. If you cant treat your tank with copper (corals or inverts or sensitive fish) I would say Fresh water dip all your fish... and hope that deals with the worst of it...

They are also passed directly between fish so QTing any infected fish could prevent or reduce effects in your tank.

Also as perisites go, these guys aren't super dangerous... they are only a real problem when the feed to heavily on one fish which could result in ulceration which could get infected with bacteria/fungi, or if your fish are overrun with them (as they are covered with them).

 

[kittyhazelton]

Since last posting this, I've freshwater dipped all affected fish. After doing that I've treated with "lifeguard" aquarium treatment per the recommended directions & have been feeding the fish garlic-soaked food once a week.
So far, there are no signs of re-infestation & the fish appear happy and healthy.