Red Tuxedo Swordtail wont eat

Question
Hi Chris,

I've had two red tuxedo swordtails for the past 11 months.  Both are male and are usually very active. Never had any problems with these fish up until this week.  

For a few days now one of the swordtails has not been eating.  It has been swimming in the bottom corner of the fish tank for a few days, and does not move much unless another fish approaches it.  It does not eat at all.  Once in a while the fish starts shaking like it has tremors.  Also notices white stringy feces today, which is odd since in has not eaten anything in a few days. It keeps opening and closing its mouth and its gills constantly, which is odd when compared to the other swordtail.

Could this be a parasite? If so, How do I treat it?

Thanks,

Scott


Tank set-up:  1 year
Tank size :  29 gallons
Fish:  1 peppered cory cat; 2 red tuxedo swordtails; three patties (type unknown)

PH: 6.8
Ammonia: 0
Nitrite: 0
Nitrate: 0
Hardness: 150
Alkalinity: 120


Answer
Hi Scott;

Stringy feces could be caused by an internal infection. Parasites or bacteria in the intestines will often be the problem. A medication containing Metronidazole is a good treatment. Look for it at your local fish store. You could isolate the one fish for treatment or go ahead and use it in the main tank in case they have it too.

I hope he feels better soon....

At Your Service;
Chris Robbins