This looks like a egg filled female tiger barb. They will lay there eggs if they find safe places to do so. I've got 12 and I'm pretty sure 11 female and one Male. All have bellies like this but I feed pleco wafers so they eat this which gives them a balanced diet from my one a week frozen treats.
Only time I've seen bloated tiger barbs was when I first got into fish. Used 5 to cycle a tank and lost one to bloated or parasite during the nitrite spike phase. They are pretty tough fish but sometimes there are weaker ones.
Funny story...I took a tiger barb tank down leaving substrate and low water for about two weeks. I look inside the tank to see something moving...it was a baby tiger barb!!!!!! So I gathered him out and unfortunately he became fish food since I had no room or proper school for tiger barbs at the time. But I learned from research and first hand that they will lay eggs. Most hatch but become food for all inhabitants including parents which explains why I never saw any. Once the barbs were removed the eggs were able to hatch predators free.