My guppy Robin is the only known male in a group of 4 1/2 (the half is a fry of as yet unknown sex) in a 20-gal. community tank. For the past few days he seemed a bit sluggish, and today I could tell that there is definitely something wrong with him but I have no idea what. All the other fish seem fine, and water is at its usual: ph 7.8, 78** F, ammonia 0, nitrite 0, nitrate 20. So I have moved him to a hospital tank (with nearly identical water specs) where I can better observe him, and his symptoms (aside from the lethargy) seem to be:

-rocking back and forth ever so slightly when he's just sitting in one position
-slightly darker than normal area around where the top of his tail meets his body
-slight redness/darkness (hard to tell for sure which) on the right half towards his underside (roughly as far back as his gill, but lower down than that); this seems to be showing through his skin (he's white there) rather than being a problem with the actual skin
-something protruding from his vent that doesn't look like poop and doesn't seem to always be there; very thin reddish thread-like things, about three or four of them at once, protruding maybe about 2 mm; I'm not sure if he has pooped since this started showing.

So, given the protrusion, I'm thinking maybe some sort of parasite, perhaps camellanus? And/or hemorrhagic septicemia? I don't know anything about either of these, but found them googling guppy diseases and either/both sound possible. Would I be wise to go ahead and treat both him and the regular tank with API general cure (metronidazole/praziquantel)? I can't use it full strength in the main tank because in addition to the guppies I've got a bn pleco and a loach (yes, I know it's not good to have just one), but I've used it half-strength before with no problem. Should I raise the temp above 78 in either tank? Other thoughts? I know pictures would be helpful but the things we're talking about here are so tiny I don't know if it's possible. If I get anything potentially useful I'll post.

Thanks in advance for any help!!



**About a week ago I unplugged the heater for a PWC and forgot to plug it back in, so the tank was at about 72 for a couple of days until I noticed when feeding the pleco that the water felt much cooler than normal and realized to my horror that I had been freezing my fish out. So that *may* have precipitated this. :(

I will agree that it sounds like a parasite, and the course of treatment that you mentioned sounds like a good idea.

As far as raising the tank temp I would wait and read the directions on the meds.
I know that raising the temp for ick treatment is recommended.
thankfully that is the only thing I have ever had to treat for.

Well, I woke up this morning to find Robin dead, so I'm guessing he must have had this for a while before I saw it. Definitely going to treat the rest of the tank; wish I could treat it full strength but don't want to hurt Queenie (the loach) or Flo (the pleco).

Sorry to hear your loss, :-(
Again I can't stress how important it is to follow the instructions on the meds.
and yes a lot of meds do say to do half strength for scale less fish or if you had invertebrates.

Sorry about your fish, I hope you find the root of the problem!

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"Being ignorant is not so much a Shame, as being unwilling to learn".-- Benjamin Franklin

It does sound like camellanus, which I've heard can be hard to treat. I've been told to feed medicated fish food, but I would do some online research and speak to a few others with more experience before you choose your meds. One unlucky fellow blogged about a particularly resistant infection and recommended fenbendazole, which he got from his veterinarian under the trade name Panacur. He was given instructions on dissolving it in water and soaking blood worms in it and then dumping the worms, water and all, in his tank. So, as I have no experience with the nematodes, I can't say for sure whether this medication will work or the safety of its use with your fragile fish but in case the meds you tried don't work, I thought I'd at least give you a lead on something you can research and ask around about. Good luck. Fish diseases suck. :(

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10 g planted community, 10 gallon danio/RCS tank, 10 g ghost shrimp grow out tank, 10 g blue pearl shrimp tank, 75 g in the works.

Thanks everyone.
Cadiedid, I actually read that same thing about the Panacur. I'm going to try general cure at 1/2 strength first and go from there; I have no evidence that any other fish are actually infected, so I don't want to go too crazy finding treatments for what may not even be a problem (hopefully!).
The general cure says nothing on the box about scaleless fish, but I've used other API stuff at 1/2 strength on them before with no problems (I used full strength on Robin as he was quarantined).
Also says nothing about temperature, so I left that alone.

following the directions on the meds is paramount.