FAQs about the "Green Wolf
Eel" , (Congrogadus
Pseudochromidae, subfamily Congrogadinae...
Related Articles: Dottybacks,
Related FAQs: Pseudochromids 1, Dottyback Identification, Dottyback Behavior, Dottyback Compatibility, Dottyback Selection, Dottyback Systems, Dottyback Feeding, Dottyback Disease, Dottyback Reproduction,
Here's a beauty at
Morgan Lidster's Inland Aquatics in IA.
Peacock wolf eel in distress
Hello fish friends!
I currently have an 18 mo old, female, captive bred, Peacock Wolf Eel who has
abruptly taken a turn for the worse. We are her third facility, and I have had
her about 5 weeks. She is currently housed in a large round holding tank, alone,
and her condition is something I have never seen. I browsed the internet and the
only thing close to her condition is something similar to a case I read about on
She was in great condition when she arrived, very active (for a wolf eel) and a
normal appetite. She ate for me the second day after her introduction to her
quarantine tank. About 8 days or so after she arrived,
I found her laying on her side. To be honest, I thought she was deceased and
when I went to net her, she went upright and somewhat swam away from the net.
Since then she has had an ultrasound and x-rays with no abnormalities or
alarming findings. She is now refusing food and has serious swimming/mobility
She seems somewhat interested in food when it enters the tank and once has taken
it in but immediately spit it out.
<This is not uncommon on certain fishes when internal parasites are present.
Another cause may be thyroid hyperplasia (caused by iodine deficiency.)
When she tries to swim it is more like a hopping motion. She has use of her
pectoral fins and is very alert and aware but to me it seems like she is
suffering from some sort of paralysis from the rib cage and lower.
She does react when you touch/pinch her lower tail area, but she doesn't seem to
be able to move it on her own. I read about the green wolf eel that had a goiter
and paralysis issue that was aided by iodine supplements
<This is true and probably the case here>
and I'm now more hopeful then I was. I’m wondering (and maybe hoping because I
am at a loss) that this may be due to some vitamin or iodine deficiency?
<or maybe both>
Like everyone, I do not want to lose this animal over an issue that can easily
be fixed so I am reaching out in all directions for any advice or suggestions
you may have for me.
<I hope it´s not too late, unfortunately the symptoms of these deficiencies are
only visible when the problem has been present for weeks or months, because your
eel is not taking/swallowing food. The only route here is to add them directly
to the tank water. Eels can go through fasting periods for weeks with no
problem, so don´t be concern for her not taking food for a while as long as it´s
not emaciated. hope this helps and please keep me posted.>
Thank you for your time and your thoughts.
Green Wolf Eel (Congrogadus subducens)
I just wrote in last week regarding an unknown hitchhiker and as always
received quick and prompt replies. Thank you again and in advance!
We've had our Green Wolf Eel for over a year now. She's been the model of
health and as hardy as promised. However, maybe slightly less than a month
ago she began to turn down food. She would eat but seemed to go slower when
swallowing as opposed to just inhaling pieces in one big gulp.
<I see... in your pix>
I had read a while back on here an old FAQ regarding the same animal turning
down food. I had remembered reading you'd seen them go off foods for months
and advised the person to add vitamins and keep trying. I've
done just that and since this started she'd take a piece here or there. No
where near the amount of silversides she normally ate.
I know behavior is a tell tale sign with fish as well as water conditions
and other signs in tankmates. However, we've been doing our regular
maintenance, conditions have all been at the ideal range and tank mates are
all normal as usual. Even she was. I noticed even a week and then two weeks
after starting to turn down food, she still stuck to her daily schedule.
During the day her and her Snowflake Eel BFF would leave their cave, move to
the other side of the tank, hang out for a while, then move back when it was
dinner time and stayed through the night. I decided to continue taking
the advice and just waiting things out. While the food was a sign of
something, she still seemed exactly the same.
However, as of two days ago she slowly started laying oddly, moving in quick
motions as if it was uncomfortable to love, and shortly after began laying
on her side as a fish does when something is wrong. She had slightly
<Likely related to the tumor here>
Our Snowflake Eel has become very big and no one told him. So he tends to
shove himself at any cost into the tiny spaces our Green Wolf will lay.
Ever since she's been laying on her side he hasn't alternated his sleeping
spots, as he usually goes from "cave" to "cave." He's made them all over the
tank. He hasn't left her side since then. I thought it was possible because
he was shoving himself in with her, that she had no choice but to lay on her
This morning when I finally took a look at the tank, she was still on her
side with occasionally lifting up her head. She'd lift it like she was going
to move the way she normally does, just switches positions, but never moved
an inch. Not since this morning.
This evening I noticed a large bulge. Very large. I had read another post on
here about a Green Wolf Eel with a bulge in a similar spot but the picture
shows the Wolf Eel upright and color looked good. You alluded to a goiter
condition. What exactly is that?
<An endocrine tissue growth related to deficiency in iodide-ate>
Is it something that just happens so suddenly? Is it fatal?
<Is very likely either a goiter or other tumor>
I know you can do a diagnosis on a picture so I won't ask for one. If you
see the picture and read the description and get an idea on anything I can
try, that's all that matters to me. I just want to know what I can try to do
without being positive on what's going on. She seems miserable. She has been
so hardy this whole time.
I do know vitamin deficiencies can cause problems like this.
<Yes; particularly B's>
I have a difficult time getting both "Eels" to take vitamin soaked silver
sides. They are so picky down to what part of the fish they get and even how
I position it on the tongs to hand it to them. He gets vitamins, but I took
it as all food should be soaked and that's not the case with them.
Would that still happen this suddenly if a vitamin deficiency?
At this point I doubt I can reverse this if due to vitamins. Since she's
refused food for so long and now can't get up. Also, I couldn't find a
diagram of their organs. Could this be eggs?
<Mmm; no... gonads are further down the body>
I mean, it's not your typical little fish so I'm not really sure where they
would have... lady organs. It's weird to realize I don't know what organ is
there and that could probably be a big clue.
Any advice or suggestions on what to do for her and how if any way to make
her more comfortable I'd really appreciate it. Breaks my heart to see this
happen and our Snowflake gets picked on by everyone in the tank. Everyone.
When she sees she snaps at them as he runs away. I don't know how he's going
to be ok without her. I do know all of a sudden he's shoving herself in
these figure 8 positions just to be next to her since this happened. I feel
they have a 6th sense on these things.
The Snowflake also doesn't get bullied to a point it's dangerous. He's
afraid of everything. My hermit crab, our cleaner shrimp, our Tang doesn't
like to let him eat, he's an easy target. However, he's doubled in size so
he always gets his food. I just sometimes have to give bribe food to the
little fishes so they let him eat! No worries!
Thank you so much for just having a site where we can write in these
questions and concerns. I wish there were more experts available for these
fish. Dog or cat you just take them to a vet. But with the fish it's easy to
feel helpless in these situations, so thank you.
<I would get and use an I2 solution like:
with or w/o actually testing. Applied directly to the water... Bob Fenner>
Re: Green Wolf Eel (Congrogadus subducens)
L'il Jen here again! Thank you for getting back to me so quickly. So I did
some research on your site about iodide. I was never good at chemistry so
it's a bit confusing but I think I get the gist of it. We have been dosing
the tank with Kent Marine Iodide. Is this brand ok?
Is it the same as the link you sent me to the SeaChem version?
<Don't know re their specific formulation; but very likely similar>
The SeaChem description also spoke out against Lugol's Solution, which I
believe you or one of your colleagues had actually recommended.
<Mmm; not I>
So should we be looking for a different brand? I saw some measurements
listed in the FAQ regarding which Iodide to use. All I see in this bottle is
a guaranteed analysis of 0.0794.
<? This number in reference to what?>
I'm not sure at all of this is relevant for you in determining if the Kent
Marine Iodide is sufficient.
We had been dosing weekly and not daily. But yesterday I did do a daily
dosing and we plan on getting a test kit ASAP to check on the levels. Will
switching to daily dosing actually make a difference?
<It might well do so. The material can/does leave solution quite quickly>
Will it help speed up any chance of recovery our Green Wolf Eel has?
It may be a coincidence but when we checked on him today the lump had gone
down substantially. It is still there but definitely not protruding as much.
Every so often he does try to move but it seems like the half of him
above the lump is the only part that moves. My boyfriend believes it maybe
is causing some sort of paralysis to his lower half. I'm not sure if this
even possible. Does it sound plausible to you?
<Can only speculate as to the causes here... is this chromaffin tissue
involvement? Derived from what? A nutritional deficiency like B12? Other?>
We will continue doing daily dosing of Iodide once we test the levels going
forward unless you advise against. I just am curious, if we find this may
have been the problem, how quick should we expect the recovery to be?
<Days to a few weeks>
Would it happen right away? Slowly? I just want to be able to find some hope
that it's working. Seeing him lay on his side like this is just devastating
and a horrible feeling not to be able to comfort them!
<... slowly as in stated above>
I also read that if only one fish is showing symptoms similar to an Iodide
problem (should I be capitalizing that word?), then you could actually rule
Iodide out as a cause. Do you agree with this statement? I figure it's
possible that he's just sensitive more than the others to it, and perhaps
there are other symptoms that we may just be missing at the moment.
<Spelling is fine...>
One last thing, if you don't mind! Our Kole Tang has always slept in the
little stone cave we bought at the store which is next to our Green Wolf
Eel's cave. The Kole is not a sweet fish, like not ever. Or Green Wolf Eel
has always had the patience of a Saint when it comes to the little fish
playing tough, another trait that makes him so special.
In the past, when the Green Wolf's head was too close to the opening of the
Kole's "bed," the Kole would "fin slap" him repeatedly. Even with the
Snowflake next to the Green Wolf, this Kole will shove his "tail fin" right
in there mouths to try and push them back. It's shocking and always shows
just how passive our Snowflake and Green Wolf can be.
Since the Green Wolf became sick as I told you previously, the Snowflake has
not left his side. Which means he's taken over the Kole's bed in order to be
able to fit. The Kole does have another spot he alternates between at
night, so he can feel safe and is safe. He's just sort of a horrible fish.
Him and our tiny Rusty Angel run this tank. With two large Eels, the little
fish are in charge. It's terrible!
Now that the Snowflake is in the Kole's home and our Green Wolf Eel is
pretty stuck right at the opening of the Kole's home, he's been relentless
to our poor guy. He is nonstop in both their faces, but mostly the Green
Wolf. He's kicking up sand in his face, sticking his "tail fin" (right
word?), literally sitting on his body, and he even pooped on him!!!
I know they can get territorial, but he's a bully, and this is crossing the
line! I've had to spend time watching him and making sure he cuts it out.
Usually a finger point has always controlled my fish enough to know to cut
it out. This one though, he just stares at me and keeps doing it. So my
question is, what can we do!? He's clearly not a threat to the Kole and the
Snowflake runs and hides quick, but the Green Wolf can't move. My boyfriend
and I were thinking of moving him. I believe I read on this site about a
timeout box. Using a small container of hermit crab tank. We do have one but
I'm not sure how easy and stress free it'd be to take him and stick him in
there. All though the idea of sticking him in a timeout box in front of all
his minions, enthralls me.
<I'd catch (use two nets) the Kole and give it a "time out" in a plastic
floating colander (like for spaghetti) for a day or so>
The Green Wolf is about 18 inches long. He's under rock work right now. I'm
not sure how we'd go about picking him up on a good day, let alone when he's
seemingly suffering from something. We don't know if that's safe to do
or even the right thing to do. He doesn't seem to bothered by the Kole but I
just can't stand it. He's bullying and I hate a bully! I would go so far as
to say his behavior is eerily similar to our Undulated Trigger, and they
are known as being psychopaths. He was placed elsewhere a long time ago.
Thank you again so much for this website. I again cannot express enough how
helpful this website is and how nice it is to find others who understand
that neurotic panic we can get about our fish. Some people point out it's
not the same as a dog or cat but it's nice to be among people who know
that's not true and take it seriously. I also love your tell it like it is
approach with some who can be a bit difficult. Especially the ones who
refuse to follow grammar rules!
I hope my grammar is up to par! I may have jinxed it now. I also want to
point out I may have kept saying him with the Green Wolf and previously her
in the last email. The color indicates it is a female. However, we've
always used the pronoun him and I try to be accurate when writing in, but
can easily forget.
Thank you so much and I hope you enjoy your weekend. My fish give a big
thank you too, for your care and help to all the fish everywhere!! I
apologize for all the words in this email too. I always try to say just a
little, and it never works out. I'm Italian and from Jersey so it's a very
talkative combination. I apologize!
<Cheers dear. Bob Fenner>
Re: Green Wolf Eel (Congrogadus subducens)
Thanks for getting back to me again so quickly. I had been daily dosing
Iodide for the few days since we originally spoke and I swear the bump went
<Ah yes; tis a real cure>
Even now it's not very noticeable. However, some time in the past 24 hours,
he's developed these white patches/sores. I searched a bit, and nothing is
worse than looking up spot or white anything with fish. All I ever get back
is Ich. I found a few things matching some symptoms, progressive lost of
appetite, laying on side, lump, sore, but not all of them.
At this point, while I was hopeful for the chances of a recovery, I no
longer am. His color has diminished, he seems incapable of moving the lower
half of his body, the sores could only be the beginning, and I feel he's
just in a state of suffering.
<Mmm; I would not give up>
He started off with the Snowflake Eel in my boyfriend's 55 gallon tank.
Which he upgraded weeks later to a 75 Gallon. My boyfriend's care in the
beginning was typical of probably most beginners. He thought he knew enough
and rules be damned. But Douche (Green Wolf Eel), and Snakey (Snowflake
Eel), amongst others, roughed it out. Once I took over they grew and
thrived, with rules in place and all advice taken!!
I just don't know in over a year what could have brought this on. I don't
know it matters for him at this point. But if it has something to do with my
care or a mistake I made, I couldn't live with myself. I've got others in my
care and it just scares me that they aren't being given the care they
deserve. From previous write ins to your website, I've never had a mistake
pointed out. But, is it possible that he is suffering from something that
just isn't affecting (effecting?!) the other fish?
Everyone else has their appetites, their energy, we've had breeding of
snails and cleaner shrimp, and I'm told breeding is always a sign of a
<Usually one end of the spectrum or t'other>
We've got a fair amount of hitchhiker type worms and snails as well as store
bought. Growth on rocks and algae on the glass, another indication of a well
off tank. The water clarity is good and my boyfriend tested this weekend and
found the water parameters are all within the necessary range in the booklet
(API Test Kit).
I know it's like literally just pulling stuff outta you know where for you
to guess what's gone wrong. At this point I feel what I need to be focusing
on is what to do next. His wounds in his condition regardless of origin in
assuming just add to his diminishing chances. I've enclosed photos. From
your experience, do these seem to be bite marks? I thought it looked more
necrotic as the rest of his skin in the light just looked not healthy. I
enclosed a photo of lump as well as his surroundings.
<Could be something internal, parasitic... genetic. Some Congrogadus do
well, some do not long term>
I've noticed the Kole Tang hanging there as usual since it was his bed, but
I swear he's got a malicious look on his face while he's over there. I'm
currently keeping watch in our tank to see if I can observe anyone picking
on him. I know what puffer bite marks look like, and it wouldn't be Snakey,
only other fish tank mates are a File Fish (Aiptasia eating kind, not sure
of scientific name), and a Rusty Angel. I don't see how they could bite in
My boyfriend suspected maybe bristle worms because he's been laying in sand
for so long, but I don't know if I see them coming out of rock like that and
onto him. I also stay up sometimes very late. I check the tank
periodically sometimes until morning and haven't noticed anything on him
like that. I also don't think the Kole Tang has the guts, but I do think
he's evil. If it does look like bite marks we'll be "locking" the tang up
So, aside from the frustration invented and desire for identification if
what I'm looking at is necrotic flesh, or bites (please!), there's just one
last thing I'd like to ask.
I'm thinking that because of his suffering and the state of his condition,
perhaps euthanasia is best at this point. I'd want the same for a dog in
this condition, and I believe my fish deserves the same consideration. I
read your site and I know Clove Oil is recommended. I know you advised 30
drops. Is that the same with a fish this size?
<Yes; or more... >
He's 18 inches long and I'm not quite sure how to convey the girth properly.
Also wondering, is it ok to just take the rocks apart and grab him, gently
of course? We are due for a water change and I told my boyfriend to hold
off. They stress me out worrying about it stressing my fish out. I hate the
way some people and some in pet stores just stick their hands in and move
stuff around with fish in there.
So naturally, thinking about how we get him out and it scaring him, scares
me. I enclosed a picture to show just exactly his position. It's not going
to be possible to net him as if he were moving, will it? I never netted the
big ones so maybe I shouldn't speak to it, but he's just a big guy. I don't
see we can do that.
<Easy to remove with a large net if this is what you want to do>
Should my boyfriend use his hands? Is it safe?
<Could and is safe, but I'd use a large net>
Should he avoid the wounds as much as possible? It's killing me to do this!!
I know our Snowflake we have to watch out for if putting hands in because
they have dirty mouths and can cause serious bites. But if it seems he can't
move his lower half of his body should we be ok doing so?
I just do NOT want to hurt him and I hate the thought of scaring him before
passing, but I just know if he's suffering it's the lesser of both choices.
It's the right thing to do. Would it be advisable to get a pair of those
gardening gloves they recommend for handling the rocks? The really long ones
that go past your elbows?
<Dishwashing gloves; long ones, are better>
Sorry for all the questions. I just don't want to do the wrong thing and
cause him poor pain. As of now, all the fish are their normal selves, Douche
was/is the hardy one, so I'm assuming it's unique to him. I know, you
Once we saw the wound though, my boyfriend thought maybe this was parasitic
in nature. Warned me against putting my hands in the tank. I have to feed my
angels (all the inhabitants of tank), so I stuck my hands in! Narrow
Lined Puffer, Douche, and Snakey are target fed with tongs. So far nothing's
crawling out of me, so I'm assuming I'll live another day. If it were
parasites, would they be a danger to me? If it were, would it have become so
dire so fast?
<You won't catch anything from the fish, or tank water if you don't have
cuts, breaks in your skin>
Just to reiterate, he stopped feeding a month ago except for a piece of food
here or there. Literally, he'd have maybe 1 piece of silverside once a week
or every two weeks. Then laying on his side, although could switch
positions, then to the lump and possible paralyzation of his lower half
below the lump, to now having sores. All after the hunger strike started
exactly one week ago.
I'm not worried about me so much as them and especially Douche's suffering.
So if you can basically just share with me your thoughts and opinions on
what should come next. I want his suffering to end. It just kills me to
watch this. He was a truly extraordinary fish. Truly. To see him so defeated
is a somber reality check. Makes me think of the millions of fish in the
oceans, all in jeopardy of a similar fate as the oceans get warmer and
I always try and remember how lucky we are to have these fish with us now.
I try and remember that while I don't necessarily agree with how many fish
we take out of the water for the aquarium trade, and how careless some can
be with them, that some of these species days can/are numbered. At least I
get to witness it up close just how incredible they all are. Right down to
the little peanut worms.
Thank you for help and kindness and understanding with my many questions.
Thank you for understanding that it always helps to have a pro tell you what
the right thing to do is! I often worry I'm not educated enough to be taking
care of them, so your guidance and that of your colleagues is essential to
providing the proper care.
<The choice is up to you. I shy on the side of being conservative in such
matters; waiting, hoping for the best>
PS: I wrote in months ago and had told you I couldn't find the option to go
to the next page on the WWM Google search results page. When searching again
I noticed it using my cell phone browser (Safari), and my tablet
However, even though it looked the same as desktop, I figured that could be
it. So when I requested a desktop site using Chrome on my tablet, the page
reloaded with the page numbers showing on the bottom for me to get to the
next page of search results.
I just wanted to pass that along in case someone wanted or needed to know.
I know a lot of people probably use cell phones or tablets or iPads and may
run into the same problem. Not a huge thing. Just helpful to continue
browsing the results! Thank you again for everything.
<Certainly welcome Jenelle. Bob Fenner>
Green Wolf Eel Growth 1/20/17
I wrote in months ago regarding a Hawaiian White Spotted Toby with damage to
the eye and you provided much needed advice! Unfortunately, she passed away
a week later. She was in pain so it was for the best. I'm grateful for this
site and being able to ask for help on something without a fee (like so many
websites nowadays) is incredibly generous. So thank you again and in advance
for any help provided!
I did do a search on here for the problem I'm inquiring about but could not
find anything related. Also, on your website when running Google search I
couldn't find a way to go to the next page of search results. Was this just
<The "next page"? The links on our pages should all be functional. Was this
on Google's work?>
I also searched Google and could not find anything either. My problem has to
do with a white bubble appearing on my Green Wolf Eel
<I see this in your excellent photograph>
and of course results were coming up as anemones, when I tried to eliminate
those results having to do with anemones or corals all I got back was Ich.
So I tried and I apologize if the answer is hidden somewhere and I missed
The details are- we've got a 75 Gallon tank and one of those inhabitants is
a Green Wolf Eel (not a real Eel, so many names not sure which one to use!)
<Ah, yes; a Pseudochromid... MANY fishes (even non-fishes) called eels for
having long bodies...>
named Douche. I'm sorry for the bad word, we thought he was kind of bad when
we first got him. It's an ironic name now because SHE is actually as sweet
as can be. Very motherly. But I say he so ignore the misuse of pronouns!
Douche is attached to the hip with a Snowflake Moray Eel named Snakey.
Snakey doesn't breathe without seeing if Douche does it first. Snakey
doesn't sleep without Douche, usually tearing the sand up to make sure he
can fit underneath Douche.
We have no corals, just live rock, and no Lion Fish. I noticed yesterday a
growth on Douche's face. It looks like a giant white head! Or a puss filled
wound. But I'm not sure if they can even get that as fish. His eating is
fine. He ate last night, his silversides,
<Do broaden this diet... it's deficient in B vitamins... Needed by all life
on this planet>
like always and he was fine. We do have a serious picky eater problem in our
tank. We dose with vitamins but any attempt to soak their food in vitamins
has failed for Snakey and Douche.
<? Well, if placed in the water, ARE getting inside your marine fishes>
If I could get Douche to eat it then Snakey will. So I feel that may be
relevant in case this is related to diet. If so, any other ideas? When I do
try forcing it he bites it, shakes his head, goes to the glass where I am,
and then spits it out. Spiteful!
Douche does like to do this thing I call "chasing his tail." I can't find a
lot on Green Wolf Eels but from observing him a lot and I literally mean
hours every day for the past year, it's totally normal. He just swims in
circles and puts his mouth on his tail like he's trying to eat it.
Identical to a dog. Very dramatic, tends to do it near dinner time. I feel
like he's just saying "I'm so hungry if you don't feed me I'll eat my tail!"
He gets fed everyday. However, sometimes he does this spinning in tight
spaces and I hear him hit his face against the glass or a rock. I'm not sure
if this will end up being relevant or not.
He's large, maybe 14 inches (I'm really bad at guessing that stuff), he
hides under rocks usually with Snakey, comes out same time everyday when he
knows it's time for food. He's a gentle giant. He will eat fish that fit in
his mouth but at the same time it's like he knows who he can't eat.
We've got a File fish (the one they sell for Aiptasia)
<Likely Acreichthys tomentosus>
and while he's grown a bit he's still somewhat bite sized, but Douche never
tries and they actually end up sharing a cave often. The File Fish has
actually gone for silversides that Douche has in his mouth!!!
I don't believe this to be Ick at all because it's just this one spot. Like
I said I'd refer to it more as a bubble. I can see it is raised. He's
behaving normal, eating, pooping, playing, sleeping, as he always does. I
just want to know if this looks like something to be concerned about or
maybe a disease I didn't stumble upon yet. I don't think it could be a bite
and again we have nothing that stings. We've got two Cleaner Shrimp, 2 Camel
shrimp and a Coral Banded Shrimp who take care of parasites (I hope they are
doing their job), so I'd hope that risk is minimal.
(I know those shrimps seem like a bad combination, but the 4 of the little
ones actually share a rock together, and our Snowflake would never eat them
because he's terrified of his own shadow. When he sees a shrimp he runs and
hides under Douche. He's "special." The Coral Banded does try to get the
shrimps but for 7 months now has yet to succeed.)
<Will likely in time. Perhaps during a molt>
We just did a water change this weekend. Our pH is 8.2, Ammonia is 0,
Nitrite 0, Nitrate 0, Salinity 1.022.
<I'd raise, this, keep near 1.025>
Douche and Snakey are the only remaining members of our "Original Members,"
the others were a Lion Fish who passed last year, the Toby, and an Undulated
Trigger who we realized was the Spawn of Satan (my boyfriend picked him
before I knew anything about saltwater tanks or fish, what a shock he turned
It's important to me that he stays healthy and happy. He's the greatest and
so smart and it would kill me if anything happened to him, but most of all
it would kill Snakey. When our Toby passed his best friend our Immaculate
Puffer totally changed his personality. He didn't swim a lot, he hid all
night (which is actually normal but with Little Puff they played all
night), he was never the same. I'm afraid the same would happen to Snakey.
He doesn't feel safe without Douche.
I take care of them daily and my boyfriend maintains the tank. I'm
incredibly involved and I just can't think of anything that changed or
anyone in the tank who could have caused him harm.
I'm attaching a picture and I appreciate you taking the time to read my
rambling on and for having this site in general! I spent hours the other day
reading all your FAQ's on all my fish and it is so informative. Thank you
for the information!! I'm so sorry I talk so much!! :)
<I fully suspect this "growth" is resultant from a physical injury... a
"bump in the night"; and will likely cure itself in time. I would NOT treat
the water, but continue on the schedule you list here. Be of good life. Bob
Re: Green Wolf Eel Growth
<Hey "Little Jen">
Thank you so much for the quick response and reading all my many words.
Since I wrote you which was when that picture was taken.... the "thing"
changed. I swear it looks like a pimple! Now it looks like a popping one.
Does this change things?
He's waiting for me to feed him as we speak. He came from the back of the
tank to the front when he sees me and knows it is time for food. So good
thing, I guess. I'm attaching a picture of the change. I'm hoping the guess
on it is still the same and it's not some sort of scary monster parasite
Thank you again a million times!
<Cheers, Bob Fenner>
Green Wolf Eel Compatibility
Hey Bob and crew! I have been pondering a Congrogadus subduscens
for a while now. I have a good grasp on this unique fish but am unclear
as to invertebrate tankmates. I know they will decimate shrimp, crabs
and hermit crabs. I have however, had no luck finding information as to
how one would get along with larger snails or urchins. Thanks,
<Hard shelled Gastropods should be fine, as well as urchins. Bob
Lionfish/Wolf Eel? comp. -- 08/05/09
While I feel like I should be able to answer this question from my own
common sense/experience, I nevertheless feel like I have to ask: I have
found a very nice green wolf eel about 6-8 inches long at a local pet
store that I want to buy for my fish only tank; however, the tank has
two Lionfish in it at the moment, a 5-6 inch Dwarf Zebra one that is
very docile and quiescent, and a rather vivacious 6-8 inch Volitans.
From past experience I would say that my Dwarf Lionfish is generally
the one that approaches cleaners I put in the tank (Arrow/Hermit
crabs...unfortunately I've had some bad luck with Arrow crabs and
the Lionfish's food turning the crabs into food) and tries to stare
them down, while in general I've never seen the Volitans do that.
However I do not think the Dwarf's mouth is large enough to swallow
the Wolf Eel, but the Volitans mouth can definitely open wide enough to
envelope the head and obviously the tail to the eel.
<See, you already answered the question from your own common
sense/experience. If it can be swallowed, it is endangered.>
I heard from a friend that so long as the eel is longer than the
Lionfish, there shouldn't be a problem, but the Volitans and Wolf
Eel are basically the same size. Because the store's tanks are tiny
cubicles, I highly doubt the eel will grow any more while there, and
the only other tank I have is reef tank, so I couldn't put it in
there for a while.
<I'm sure it will grow, but slowly.>
The store employee suggested putting a tank divider in to separate the
animals until the eel grew large enough, but my tank is a 55 gallon
bow front and dividers for that are hard to find and would separate the
tank in a way that would severely limit the space for my active
<I would not add another fish here. It will even become narrow for
the larger lionfish with time.>
I suppose the easiest option in this dilemma is to forget about the
green wolf eel, but it is a very tempting creature, very bubbly from
what I've seen and heard of the specimen that's been in the
store for a while. And while I'm not so concerned about this, what
would your opinion about placing a Green Wolf eel in a Lionfish
<A larger eel in a significantly larger tank: maybe. If the P.
volitans was removed from your tank: maybe. Your current setup: I
have green wolf eels been known to pick at Lionfish like Angels and
<No. Cheers, Marco.>
Green Wolf Eel, fdg. 4/18/09
Can hole/frozen Anchovies be used for feeding rather then say,
They are not frozen in any kind of brine
<Anchovies certainly could be used occasionally if they're
accepted, but because they're so oily, it would be unwise to use
them too often. Partly, the large amounts of oil could harm your fish,
but also oil tends to make a mess of water quality. So by all means try
them out once a week, but don't use them as a staple. Much better
to concentrate on a mix of white fish and invertebrates, in particular
species without thiaminase and with low fat/oil content (see WWM re:
these issues for more). Congrogadus are fairly adaptable fish, but will
go off their food in the "wrong" tank. Cheers, Neale.>
Wolf Eel System\(Over)Stocking\Health\Feeding.
I have had this little (big about 13in) guy for about 5 months.
He is in a 55gl. tank with lots of live rocks and caves. He lives with
Lunar Wrasse about 11-12in long
<Needs 75 gallons as an absolute minimum.>
a Huma Huma Trigger about 5-6in and a Fox face Rabbit fish about
<You are severely overstocked.>
All has been good, until 2 days ago I noticed that its left eye had a
bright green glossy tint to it about the same color he has on the top
of head (his body is a dark greenish-brown). Now today the eye is still
glossy green but it looks like it may be swelling up some.
<Likely a physical injury>
He is still eating OK, his sight seems unchanged, he sees if I hold a
gold fish up to the glass.
<Please tell me you are NOT feeding him Goldfish, one of the worst
foods available. Read here: http://www.wetwebmedia.com/goldfshfd.htm
The other fish don't pay any attention to him so I don't feel
that he is being picked on.
<That you can see, Lunar Wrasses are very aggressive.>
Not sure if this is even possible but, the only thing that I can come
up with is that with the color being a bright green is algae. could
algae start growing on a fish?
<It is possible, but unlikely>
The rock he is under most of the time does have a lot of Hair Algae on
<What are your water parameters, filtration and skimming?>
Any info would help. Also I attached a picture, sorry I used my cell
<Need a better picture than this , cannot see any real
Chris in WA
<Mike in FL>
Demon Green Wolf Eel... moray? Not the
Pseudochromid/Congrogadid 12/11/08 Hello, <Hi
Ralph.> I hope you are all doing well and enjoying the Holiday
season. I have done quite a bit of research and was hoping you might
have some suggestions for me. I have a Green Wolf Eel that I rescued
from a friend who had it in too small of a tank. I have relocated him
to a 55 that I had up and running sitting empty. He is doing fine
eating well, perhaps a bit too well. I have tried to add other fish to
the tank with no luck at all. I made sure he was fed and the light were
off in the tank and his snack list is costing a small fortune. Several
various damsels from 3 stripe, domino and inch long Sgt. Majors. They
lasted less than 5 minutes. He was able to take out an Atlantic spiny
puffer in a week and even did in 2 different lion fish. He is
relentless with hermits, takes chunks out of Chocolate Chip Starfish
and if you blink any species of shrimp is gone. Ok well I have not
tried a Mantis Shrimp yet but you see my problem. Any suggestions on
what I might be able to try in there with him that might stand a chance
of living a bit longer than a week? I have quite a bit of rockwork and
a clear PVC tube that he sometimes likes to hide inside. I know I could
relocate him to another tank, stock the 55 and then place him back in
the 55 after the other fish have settled but wanted to know if perhaps
there were any other options. Certainly the cost is adding up. I was
thinking of a Niger Trigger but after he took out the puffer and lion I
was hesitant to add them. Thanks so Much and please be sure my Green
Wolf Eel gets put on Santa's Naughty list. Ralph <Almost sounds
like a Green moray eel, not a Wolf eel (Congradus sp.). The problem
here is that recommendable fish large enough to be safe from the wolf
eel would be too large for the 55 gallon tank. If you want to keep it
with tank mates, I'd recommend setting up a significantly bigger
tank with fishes too large to swallow and introduce the eel last. It
also sounds as if your eel needs more food, generally Congradus eels
are not that bad mannered. In larger tanks they can be kept in pairs or
small groups, and have been bred in captivity. Cheers, Marco.>
Green wolf eel and Jeweled Moray 07/03/08 Hi everybody hope
all is well... <Hello Josh.> So at one of my local LFS they have
this beautiful green wolf eel (Congrogadus subducens), it is beautiful,
strangely it is red in color. <Yes, they sometimes occur in this
color. There is some variability, and in addition they are able to
change their color to some degree.> instead of green and it is about
12 inches long and as think as a ping pong ball. At home I have a
jeweled moray who is about 22 inches long and as think as a tennis
ball. My question is would I be able to put the green wolf eel in my
tank without it becoming a quick snack for the jeweled? <I have seen
this combination, but with animals of equal size. Personally, I would
not risk losing the Wolf eel, because it would likely fit into the M.
lentiginosa.> Thanks for your time. Josh <You are welcome.
Carpet eel blenny not eating please help
10/2/07 Hello, Thanks for all the information you have
provided since I started in this hobby. It has been a great help.
My question is about a carpet eel blenny. <Congrogadus
subducens... sometimes placed in a subfamily w/in the
Dottybacks...> I have had him for about 5 months. He has been
doing great. He would come to the top of the tank when I would
look in and loved to eat. <This is a great aquarium species...
very intelligent... interesting behaviors> I have been feeding
him once a day due to my schedule. He would eat three or so
decent size pieces of krill each day. I give him small pieces of
raw fish whenever I am eating it for dinner. About a week ago he
started staying in his PVC cave I put under the sand bed. he
barely comes out now. He has only eaten two pieces of krill in
the past week. I have tried offering him silversides and a hunk
of orange roughy but he did not want them. He snapped at the
silverside but then returned to his cave. I have noticed his
lower lip is now a reddish orange color now. I was not like that
a couple weeks ago. When I feed him I put the food on the end of
a bamboo skewer. Is it possible he got stabbed by the tip while
feeding causing the reddish lip? <Mmm, yes, possibly> I
don't know what to do or why he is not himself. Please any
suggestions would be much appreciated. <I suspect some sort of
nutrient deficiency might be at play here from the mostly limited
list of fatty foods you list... Do you supplement these by
soaking?> My tank parameters are the same that they have been
for the past year or two. Ammonia is 0 ph is right above 8 and
nitrates are somewhere under 10 parts. Salinity is at 1.24. He is
in a 30 gallon <Small...> with a three stripe damsel, a
scooter blenny, a conch, two snails, and two hermits. He is about
6 or 7 inches long right now, I am currently planning a new 100
gal home for him. <Oh, much better> The tank temp has been
a little lower then normal, 76, since it has been colder. I just
got a new heater today to help stabilize the tank at 79/80 like
it is normally. <This should help> The tank temp has been
around 76 for about a week or a little longer. Thanks for you
help and for this great site. I am sure it has save many lives.
Kind Regards, Jeff <Do use an appetite/immune system booster
like Selcon, Biovit... directly to the water and on the foods for
ten-fifteen minutes before offering. This fish may also be
"going through a phase" (like reproduction) and just be
reclusive due to this. It should resume feeding in a week or two.
Re: Carpet eel still not eating,
Congrogadus 11/21/07 Hello again, <Jeff> I
took your advice and I ordered Selcon and vita-Chem and received
them about a week ago. I soaked the food, (krill, clams,
silversides, salmon, Mysis, brine) in the Selcon. I added the
recommended amount of Selcon fifteen minute prior to feeding and
dose the tank as recommended. I also added vita-Chem as directed.
My carpet eel will still not eat. it has been about a month now
since he has eaten. <Don't give up faith here! Have seen
this species go off feed for months> He does not move around
that much, just alternated from his three favorite spots in the
tank. I have done a 40% water change and leaned all the filters
this past week. I do 30% changes every two weeks on a normal
basis. 0 ammonia, nitrates under 10 parts, 8 ph, and 1.25
specific gravity. <Missing a decimal space> The temperature
is between 78 and 80. The red spot I mentioned in my earlier
email has since disappeared. My eel looks healthy with no signs
of disease. He perks up when I look in the tank but will not eat.
Is there anything else you can suggest to get him eating? Do you
have any thoughts as to when he stopped and how long he might
make it? I hate to see him not eat and don't want to loose
him but I don't know what else I can do. Thanks for all your
help in trying to save this amazing fish. Jeff <Again... to
continue doing what you are... I do think/sense this specimen
will resume feeding in time. BobF>
Green wolf eel is black 8/16/07 Hello all, About 2
months ago I bought a Green Wolf Eel for my high end brackish tank.
When I got him he seemed healthy with the exception of what looked like
scraping on the end of his tail. I believe this was from
entering/exiting an undersized fake coral cave at the pet store. it has
taken a while to heal up but it pretty much ok now. The Wolf Eel seems
happy. He alternates between hanging out in the live rock and venturing
out into the tank. He is a greedy eater and is somewhat aggressive at
meal times. <Yes, good signs for this Congrogadid, latter day
Pseudochromid> He shows no sings of illness or stress..... except
that he is pitch black. <This IS a sign> all the time. He is
never green anymore. At first I assumed it was due to the black sand
substrate. So I changed it to a lighter color sand. This didn't
help. He is still black as night. specs90G, Rena FilStar XP3, Magnum
HOT, Turbo Twist UV Ammonia and nitrites are at 0Nitrates are a little
high at around 60 but I don't think this is the problem.SG is at
1.020PH is 8+Tankmates: scats, monos, green spotted puffer I am adding
Live Rock as I acquire it and have about 30-40lbs so far. Diet is
mainly silversides and krill. He will not take flake or pellets so far.
The color change was abrupt and not a fading. Salinity is ok as they
are brackish in the wild. He is not bullied and has no injuries except
some residual scraping as noted above Any thoughts on why he is black?
thanks so much! <In a word, stress... this is really a marine
organism for one... s/b in spg of 1.026 or so... The puffer may be
nipping it... I'd try moving it to a full marine system. Bob
Please do send along a brief bio... and the
Congrogadinine -- 03/17/07 <Ah, yes... Will post. And you're
having no problem/s logging on? BobF> Nope, none at all.
I'm working on the freshwater/brackish blennies piece, among
other things. Specifically, I'd like to canvas your
views on Congrogadus subduscens. Admittedly, not a blenny, but
called one, so I've included it on the basis that it
occurs in brackish water (apparently) and I know aquarists
who keep it with monos & scats at SG 1.016. <Ah, yes... the
errant Pseudochromid... in its own subfamily still I believe> You
know more about Indo-WP fish than I do -- is this fish a
transient member of brackish water communities, or a
euryhaline species suitable for high-end brackish tanks?
<Have never encountered this species in the wild, nor heard reliable
accounts on how it is collected. The short answer, "I don't
know"> Fishbase confirms its brackishness, but
I can't find any scientific papers on salinity
tolerance, which is my usual _modus operandi_ before
"declaring" something a brackish water fish.
<Good to be cautious. Cheers, BobF> Cheers, Neale
Wolf eel Eggs - 10/15/06 Good evening, folks.
<<Hello>> I have written before a few times about our
beautiful wolf eel, which recently survived our family's relocation
from California to the DC area. <<Ah, good>> Wolfie, a
beautiful orange aggressive creature, stopped eating about a week ago,
and then yesterday, we were all surprised to find this large pink batch
of eggs that she (! We had always thought of Wolfie as a male, since
the bright orange coloration defied the black/green distinction in the
literature) was protecting. <<Hmm, just musing here...I wonder
what biological "cue" caused the eggs to hydrate>>
Obviously the eggs are not fertile, but what should we do with them?
<<Best to remove them before they begin to decay>> Will
Wolfie start to eat again soon? <<Likely, yes...and removal of
the eggs may speed this>> Wolfie shares a 55-gal FOWLR tank with
a small Volitans, a coral-banded shrimp, a choc-chip sea star, and a
sea urchin. Thanks for your help and the amazing information provided
on your website. <<Glad to be of service>> Franck
Re: Wolf eel Eggs - Thanks for the insights, Eric. -
10/17/06 <<My pleasure>> I thought you might be
interested to learn that the problem took care of
itself. The circle of life and all that. The
Chocolate Chip sea star found its way to the eggs and made fairly short
work of them in two separate feedings. <<Ah! Better
than 'tossing them'>> In between, Wolfie moved the
remaining clutch around a bit with her mouth, but didn't move far
from the original site. While the fish has not yet resumed eating, her
behavior is returning to normal. <<Excellent...perhaps you can
tempt her with some frozen glassworms. I find these to help
with most finicky feeders>> I assume that the eggs were a healthy
meal for the ccs? <<That they were...>> Thanks again for
the quick reply. Franck <<Always welcome. EricR>>
ID please - Green Kelp Poacher or something! 6/25/06 -
Hello, Hi there, Leslie here with you this evening.> A friend asked
me to help identify his new fish. It is something I have never seen
before. A green kelp poacher is what he was told it was. <Hmmm,
interesting name and not one I have heard before.> The fish is about
1 foot long bright green looks like a Moray but has a head that is
shaped differently. I have looked in all of my books and the web with
no luck. The head looks more like a Gramma. The fish cost him $150.00
bucks. I try to tell him don't buy anything unless you know what it
is and what it eats. <Very good advice!> Do you have any ideas of
how to identify this fish? <Hard to say without a photo but it
sounds to me like it could possibly be Congrogadus subduscens commonly
known as a Carpet Eel Blenny or Green Wolf Eel. You can have a look
here http://www.wetwebmedia.com/pseudoch.htm. They are a Dottyback
, Family Pseudochromidae.> He just told me that the fish is hiding
under his rocks and has not eaten yet. <They are much more secretive
and less bold than the other Dottybacks and hiding under rock would be
expected. It probably needs some time to adjust to it's new
surroundings. They are carnivorous so meaty frozen and fresh meaty
seafood would be appropriate. You can find captive care information at
the link listed above.> Thanks. <Hope this helps, Leslie>
Eel Blenny/Pseudochromid Question... with Dwarf Lions OK, with a
Queen Trigger, No Way 6/17/06 Hello, I have recently
come across a Eel Blenny/Green Wolf Eel (Congrogadus subduscens) at the
local fish store, but have been having some difficulty in finding info
on it. I've read that it gets fairly long in length, but
despite its size is quite passive as a Dottyback. Can you
please reconfirm this? <Please see here: http://www.wetwebmedia.com/pseudoch.htm> How
passive is it? <Quite... maybe a 2-3 out of ten...>
In my tank I have two dwarf lionfish (at the moment, inedible
size). Would these fish go alright together in the future?
<Should, yes> I also have a decent sized queen
trigger. Any problems there? <!Huge... Balistes vetula is
close to a "ten out of ten"... Not to be trusted with these
other fish species. Bob Fenner> sincerely, Aaron Raney Green wolf
eel I saw a green wolf eel in the LFS they said it would not eat
hermit crabs and was not in the moray eel family. Do you know anything
about this type of eel? <Yes... as bizarre as it may seem, this is a
member of the family of Dottybacks, Pseudochromidae. Please read here:
http://www.wetwebmedia.com/pseudoch.htm This species is covered here.
Bob Fenner> thanks, j Colgan
Green Wolf Eel Spawn - 02/03/06 Eel has eggs any
recommendations? I have a pair in the tank along with a
trigger. I am taking the trigger out to another tank, but
how long is gestation? Any help would be good.
<<I'm sending you a link to a chat forum where someone is in
their third spawn with this fish. You should be able to get
the info you seek...even ask specific questions re this
topic. Regards, EricR>> << http://www.columbiamarineaquariumclub.org/forums/index.php?act=ST&f=19&t=1488&s=645d1c240337198ac41a0a01a34fa14c
Help, we have Eel eggs! Dottyback repro. 1/18/06
I have a green face wolf eel. She just laid a bazillion eggs. We have
had her for about 1month and the pet store had her for about 1month.
How do they fertilize their eggs? Will they hatch? As far as I know she
has not been around a male eel. <Then these are sterile... will not
hatch... may want to vacuum out before they pollute your water> We
have other fish in the tank. Should we move the eggs or move the fish?
Help!!!! Thanks, Heidi <... If you have
earnest desire, please see WWM re Pseudochromid Repro., the works of
Martin Moe. Bob Fenner>
Snowflake moray and a green wolf 2/11/05 Just a
quick one, since I can't seem to find anything on this anywhere,
maybe you guys can answer it for me. Would a Snow flake moray and a
green wolf ell be able to coexist in a 46gallon bow front tank? Thanks
in advance Nick <its rather poor mix... the green wolf
"eel" is a fast and furious eater (keep sighted) while the
moray is not. Without target feeding the latter, it may suffer over
time. Do reconsider. Anthony>
-Green wolf eel with an appetite for flesh- We're having
a problem with our Green wolf eel. It has eaten 2 Lunar wrasses 1 4
inches and the other 6 inches. <Ouch!> The eel is 14 inches.
Would a Niger Trigger fish be OK with it or can you recommend another
fish? <Triggers are pretty precarious to swallow, but you may want
to choose a more aggressive species. this selection would depend on the
adult size of the trigger and the size of your tank.> We also have a
Dog Face Puffer and a Yellow Eyed Tang. The Puffer and the Tang seem to
be fighting also. But I think it more of a territorial dispute since
the Tang is new. <If the tank is too small, they may dispute
indefinitely. Since the tang is new, however, a little bickering is
expected. Hope this helps! -Kevin> Any help would be
Green Wolf Eel/Pseudochromid Dear Mr. Fenner, I have a green
wolf eel and I cant seem to find any information on it. can you help
me? <A little perhaps... this fish, Congrogadus subduscens is
actually classified as an Eel blenny (subfamily Congrogadinae) of the
Dottybacks (family Pseudochromidae) of the tropical Indo-Pacific.
It's actually not an uncommon offering in the trade... and
generally takes most all types of meaty foods with little
training...> I also have 2 lion fish, I cant seem to get the one off
gold fish, I tried starting him on frozen foods, he would not eat them,
I gave him gold fish and he loved them. how can I get him on
frozen? the other lion fish eats it but he wont. and are silver
sides a good food or are they the same as gold fish. well, those are my
questions. thanks again, Mike Mastronardi <Please read over the
"don't feed goldfish" and Pseudochromid pages and FAQs
posted on the www.wetwebmedia.com for answers to your queries. Bob
Spawning Green Wolf Eel, CCS health Hello! I have a question
about something that happened that completely threw me for a loop. I
have a green wolf eel (about 6 months now) that I had always believe to
be male due to the fact that it is an extremely vivid green color. I
had read that females tend to be duller and brownish in shade.
<Yes... a gorgeous, interesting Pseudochromid species> However,
when I came home today from school, I found my eel blenny to be wrapped
around a purple egg mass, so its female, right? <Sounds like it>
I don't know where to find a male eel to fertilize my eggs and even
if I did, I wouldn't know what to do. <Uhh, too late for this
batch> So what can I do now? I obviously can't leave the mass in
there, can I? Would it be safe to remove the mass? <I would wait a
day or two... then siphon it out> And if so, when can I do so
without upsetting my eel. (I've recently moved the eel into this
new tank about a week ago so I imagine it's a bit stressed.)
<Better to upset it, than risk the water pollution consequences>
I also had another question regarding my starfish. I have a chocolate
chip starfish that was being kept in a tank with two hermit crabs.
<Ummm...> Recently, I acquired another hermit crab that was sized
in between my two current ones. I noticed that this crab was more
active than my others. about two days later, I found my starfish
flipped upside-down and curled up. After further examination, I found
that two of the "chips" on my starfish had been eaten off.
the first thing I did was remove the three hermits and then I
quarantined Callisto. I have been carefully monitoring the starfish,
and it seems to be doing better as its moving around again. Is there
anything else I should do to ensure Callisto's welfare? <Please
read on WWM re CCS> Thank you so very much! ~Jules <Thank you,
for writing, reading, using your spell- and grammar checkers before
sending. Bob Fenner>