Unknown excretion from female swordtail

Question
I have a newly set up 60 gallon tank (6 days old) with 7 swordtails and 5 cories.  One of the female swordtails (she is clearly the largest of the group) has excreted a string-like maroon colored substance that sticks to her underside until its about 1.5 inches long, then breaks off and sinks.  The other fish have tried to eat it but immediately spit it out.  What is this excretion and is it something about which I should be concerned?

Thanks,

Greg

Answer
Well, to be quite honest, this sounds pretty much like fish waste (poop) to me.  Their waste tends to be pretty much the coloring in the foods they eat.  Considering that is was this long, it sounds to me like she may be a little constipated.  What I would do for this is take a few peas, either frozen or out of a can, take the shell off of them, mush them up a little and put them in the tank (like 4 or 5). It's like a fish laxative, it will help clean her out.  It won't hurt any of them.

If you do not feel that it is normal fish waste, write me back and let me know why. Remember, the bigger the fish, the bigger their waste is going to be.

You say this is a new tank.  Please be sure that you keep a check on the water parameters because you will be going through some spikes of ammonia, nitrates and nitrites as the tank "cycles".  These spikes will have to be controlled through water changes and cleaning, etc. until the tank gets done cycling.  Here is some info on cycling a tank, it's worth taking a look: http://www.firsttankguide.net/cycle.php

I hope this helps.  Feel free to get back to me if necessary.