Swordtail Issues

Hi
i have a female swordtail that i thought was pregnant. however right nnow she is hovering near top of tank and has a protruding sac at her anus. is this a sign of giving birth or is this a severe issue? someone please help i am new to this. thanks

More information please: http/www.fishforums.net/index.php?/topic/2330-please-read-before-posting-to-emergency-section/ and photo would be appreciated.

Tank size:29 us gal
pH:7.0
ammonia:0.25
nitrite:0
nitrate:0
kH:
gH:
tank temp:78

4 swordtails 1 male 3 female
i algea eater
several snails
all other fish appear fine but they do hover around her. this "sac" is pinkish and translucent.
this just appeared today.

newwithfish said:

ammonia:0.25
[…]
nitrate:0

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Why do you have ammonia in your water and no nitrate? Is the aquarium newly set-up? If it is, did you cycle the filter with household ammonia?

newwithfish said:

i algea eater

Click to expand...

What is the algae eater?

The "sac" is not normal, it looks like a tumour or ulcer. At the moment, I can not recommend any course of action other than to wait. If the fish starts to look stressed, switch off the light.

What do you feed the fish and how often?