Serpae tetra possibly egg-bound?

[Emma]

The preschool tank I take care of has a lively school of serpae tetras, and the last several visits this particular female is looking extremely round. This time I noticed her vent is looking swollen? She's bright, alert, eats well, beats the crap out of the other fish, no buoyancy problems, and the water parameters are good. Is she just very full of eggs, or should I be worried about that vent? 

Thanks!

-Emma

[Colu]

Could be a prolapse caused by staining due to being egg bound I would treat with Epsom salt 1 table spoon for 2 gallons for no more than 15 minutes 2-3 time's a day  as Epsom salt acts as a muscle relaxant it will help to relieve pressure and help your fish to reabsorb the possible prolapse

[Emma]

Well, unfortunately I'm only just now getting back to this - I had knee surgery! Since I knew I wouldn't be able to try your recommendation @Colu, I've had her in a 5 gallon tank with slightly salty water (2 tablespoons/5 gallons). Surprisingly, six weeks later, she's still around and still very sassy! She's lost some body condition, but this next week I'll be off crutches and I'll (finally) be able to give this a try. Thanks for the advice!