green wolf eel has dark spot/scrape on tail?? please id

I would say its all due to you getting this wolf eel too early on, long before your water conditions were anywhere near to perfect. Its was all due too water poisoning for ill effects when it comes to eels not often show soon after like with other aquarium fish, that if you did this with any fish, they would had died in a matter of afew days. But for eel like species, they all often show slow symptoms effects and suffer a great deal longer then any othr marine tank species. You not have to take my word for it if you reject my professional view in this matter, I do recall that I told you that your wolf eel will suffer somewhat, you failed to listen im sorry to say for the best thing you should had done was take it back to your LFS and placed some damsels in your tank, and waited for your tanks cycling to complete, then get the wolf eel. Metal traces in aquarium water is a extreme bad thing to start your tank out with and collect a eel species of some type and place it into a beginning cycling system. What you should had done was get this eel only after your cycle completes and that your nitrate levels are at zero, this is what you should had done.

Buddy

A eel like creature does not suffer an illness conditions as fast as most fish will, they will suffer slowly in the process and show almost nothing during a problem period until its much later on, I know this be a fact to what Im saying here, you still going to say its nothing to do with what you did?

You assume someone is being as worst to you due to your professionalism is a error of judgement on your part, for my remarks came from when you claim their were no problems during the worst time period of your tanks cycling and I told you even from the start that your eel will suffer, but it also not mean that you would seen problem issues with your wolf eel right away, for I knew their will be problems of some kind, being that is you chosen to keep this eel even after telling you it was a bad idea.

here is one of my lines I responded to you with "This is your problem, you rushed off to buy this species when your tank not even fully ready as yet to house it, you need to take yourself a step back and begin saying to yourself (need to have a great deal of Patience) "

Now, that to me dosn`t sound like im being mean or insulting to you!!

And here were I said "You bought this species long before you were even ready to own it. The wolf eel is suffering right at this moment because you simply had taken the word of your LFS provider who and which most are only concern to make their daily sales."

The point in it is really simple, most LFS only care to sell off their live stock, rather then to sell it to proper aquarium tank size or the best marine hobbyists who are very capable to proper care for that marine species.
Were you said "so we got a small damsel" one damsel fish is not enough for a 30 gal tank>
　
So young man, you say that you did your research (I did a lot of research) on what you are doing here in your tank, I say if you really did, we wouldn`t be having this discussion now. You are really in this discussion all due to trusting and relying on your LFS in what they told you who sold you the idea you can buy bacteria for your tank and then add the wolf eel. And i told you that you simply "rushed into something here to fast and too soon." You even told me that when you ran a search, you found nothing that of was help whatsoever and afterwards im trying to tell you things and your making it as if their be some attitude problem on my part. The truth be is you have this attitude problem and if you can not accept my help in what I been telling you from the start from you email request, I can not offer you any further advise on what is either wrong with your eel or any other questions that you might ask in time.

So seeing it that you seem to not accept my views or your no wish to accept the facts, and you twice, once in both threads done the very same problem, in which I knew there was a strong possibility you be posting something like this sometime following six weeks when you first placed the wold eel in its predicament.

You young man is doing the same thing as all the others who gotten some eel they had no business in having due to their tank size or experiences, that of all those who i told them their project will not work, in a matter in a years time, not one of those hobbyists had that eel species still. Like one who had a 240 gal tank and was keeping four eels, He wanted that I shown him proof that one set of eels will soon enough turn on the other and also that set would soon enough turned on one another, months later in trying to follow up on his progress, he never posted again with bragging about his eels, I guess he had his proof far sooner then he expected.

So your not the first to not listen, and you wont be the last. I wish you luck in doing the right thing for this eel for im done in any return response to your questions or other for I received twice from you a certain negative response, most likely due to your young age and that you can not accept the fact that it was your LFS who done all this to you and all I been trying was set you straight about the true facts. Bye, and best wishes Buddy

Looks to me like maybe something could have fallen on its tail, or it lashed its tail against a sharp piece or rock maybe? how is he doing thus far?

It's definitely a bacterial infection. Something caused a break in in the fish's slime and some nasties got in. The Old Man is partially correct in that water quality plays an important role in whether or not a wound gets infected and how severe the infection becomes. I don't know your parameters but generally speaking the easiest way to handle this would be to medicate a bit of food such as fd krill and feed it. My experience with those Dottybacks is that they rapidly learn to take food from one's hand but have a hard time figuring out where the food ends and the hand begins! It's a really good thing that they're not really Eels with the teeth to match! But medication is useless unless water quality is up to par.