Why is tiger barb staying in corner nose down, bloated and pale. Tetras having a go at it

Please help. Community tank. Includes 3 barbs, 2 green, one tiger. Tiger is bloated, stays in corner with nose down. If it stops swimming, it starts floating up. Scales seem to be sticking out more. Greens seems to be protecting it. Neon Tetras try to nip it (unusual for them). Can move away if it needs to and then reverts to vertical position. Mouth moving more than usual. Eating as normal

 

Overfed/early bloat. Feed blanched peas.

 

Thank you. I'll give it a go

 

:-( Not sure why. Water changed and tested regularly. Have been feeling the same for over a year. All other fish are well. Only difference is I've moved recently. Everyone had to be bagged for travel and my mums fed them a couple of times.

 

Thank you. Started with 6 but I've had 3 now for a long time.
Tiger barb rip yesterday

 

Sorry to hear about your barb one of my school also had the same problem a few years ago. All the best.