Help me please!

[Neosum]

Found a fish with an abdominal swelling.

The volume of the aquarium is 300 liters (length 2 meters, height 35, width 50)
Launched 3 months ago
13 adult fish live in.
There is no light
Temperature 29-30 degrees
Two Eheim Professionel 3 2080, three Tunze pump flow pumps at 6500 l / h
No soil
The frequency and mode of water changes every day 25%
kh 3, ph 7.0, gh 7.5, no3 10, po4 0.1, no2 0.05
JBL Tabis daily feed, sometimes shrimp

Is there anything I can do?
Thanks in advance for any recommendations.

[TwoTankAmin]

The information provided should include the inhabitants of the tank.

That said there are a couple of things that could be at work. If a female fish it may be full of eggs and ready to spawn. Or it could be full of eggs and egg bound. I can also be constipation. If the fish isn't pooping, it will swell up Causes are varied as would be the cure.

Finally, it could be an internal infection.

Also, I do not see the pictures, only the word Image where each should be.