HELP! sick guppy

[PNA]

:shock:
I've got a female guppy that gave birth last week.  I don't think she's eaten anything since!  Her tail is sort of rotting away and it kind of looks like she may have internal bleeding (red spot near gills)... but really not sure about that.
Some times she goes for the food, eats it, then spits it out.
And I see occasionally her convulsing as well.
Mostly she stays in a corner of the tank near the surface.
Everytime I look at the tank I'm looking to see if she's dead.  So if someone can help prevent that I'd feel much better.
She's in a 5 G with rasborras and shrimp.  Fluval 1 filter (been running a long time), and weekly water changes.  Everyone else in the tank seems fine.

[Aiglos]

Right after a female guppy has babies a hormone is created in her that makes her have a very small appetite, this is to give her babies a chance to survive so that she doesnt eat them, can anyone verify that  ? That is what was explained to me when I was breeding guppies,  Giving birth is also quite an ordeal for a guppy so it may take some time for her to regain her strength and get back to her regular self,   I can't explain the tail rotting though or the gills, I hope its just her being exhausted from giving birth.

[Eirikre]

I've never heard of the apetite supressing hormone Aiglos is talking about.  I have no specific knowledge to the contrary but it doesn't make a lot a sense to me from a survival standpoint.  One adult female guppy is far more likely to produce a significant amount of offspring than 50 newborn fry many or all of which are likely never to reach the age of reproduction.

I have little experience with guppies but plenty of experience with Endler's Livebearer which is at least a very close relative and is likely just an isolated  variety of wild guppy.  In my experience females eat little to nothing for anywhere from 6hrs to 2 days after birthing.  The late pregnancey and birth process is very taxing and leaves her exhausted and vulnerable.  It also leaves her both mal nurished and dehydrated as well as having her heavy minerals sapped, particularly calcium.  She is now much more suseptable to parasites and bacterial infections (it sounds to me like your fish is suffering from the latter).  She is also more suseptable to harasment from her tank mates.  Even if they all lived in perfect harmony before she may get picked on in this weakened state.  Her best chance is isolation.  If you move her to your quarentine/hospital tank she will have a far better chance of survival.  If you don't have a hospital tank this is your excuse to upgrade.  Your fish sound a little crouded in the 5g so why not move up to a 10g and keep the 5g for you quarentine tank.  If she is suffering from a bacterial infection your other fish are now also at risk since the bacteria level in your tank is growing significantly now that it has a susceptable host.  The rest of your fish will benefit from her removal from the tank as well.

There are a number of medications available, most of them anti bacterial or anti parasitic buy they are quite expensive.  It sounds like she may be suffering from fin rot but I am no expert in fish disease and medication.  I rely on isolation and frequent water changes to bring my sick fishies back to health.  some people add salt in small quantities as well to help improve the fish's slime coating but I don't use it often.

Good luck to you.  I hope it works out.