What's up with my Black Skirt Tetra?

Hello, I have 6 black shirt tetra and today I noticed three of them are bloated?
Can anyobe tell me what's up with them?
They are in a 20 gallon hex
With a dwarf gourami
6 corydoras
A pleco
2 platys
2 mystery snails
a single molly.
And two tinfoils barbs (they are being rehomed this weekend my little cousin bought them with my mom. They didn't know))
Also I think a ramshorn snail, I'm not sure. The snail just appeared one day and doesn't look like a pond snail.
temp it 78 or so, that was last reading before it broke.
I don't know the ph or anything, haven't bought a test yet
I aslo have some live plants.
Java fern
Micro swords
And some thing else I can't quite remeber the name off.

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Is the tank cycled, have you had the water tested anywhere and what pleco do you have? It sounds a little crowded to me? If you have no test kit diagnosing issues is harder because you can't rule out the basics.

 

You have some stocking issues (besides the barbs) if you want to discuss them

Could you be overfeeding? Try fasting for 3 days (don't worry, the fish will be fine without food for that long) and see if that helps. At the end of 3 days, you can feed all of your fish deshelled, blanched peas.

 

The pleco is a common pleco.
My mom should be getting a large tank soon so he will be moved there.
The tank wasn't really cycled.
I only learned about all that stuff pretty recently when researching the fish I had.
I'm very new at this fish keeping business

 

It could just possible be that they are females loaded with eggs.
Can you get a picture of one looking at the camera? I know that's a tough one.lol

 

What type of food are you feeding? Mine look like that after stealing cichlid pellets.

 

I feed omega tropical flakes.
I have tried getting a pic from tge front.
It didnt work. If they werent facing the wrong way, another fish was in the way. Ugh

 

There are a few things that can cause that; as suggested already, over feeding, pregnancy or possibly worms/internal parasites. It will be a case of monitoring with less food and ruling out each as a possibility. As for the pleco he needs a 100 gal tank or bigger, a 20gal is not big enough even for a short time, they produce a lot of waste causing poor water quality and will be stunted causing health issues. Have you been testing the water and what's the cleaning schedule?

 

They are enormous / a bit overfed females.