Internal Bleeding?

[Ft fisher]

Hello all. I've just been to my tank to feed my fish and have noticed one of my Cherry Barbs dead, and to look at it there is no signs of disease. Only thing I could see is what looked like blood under his scales inside his belly? Like he had internal bleeding or something. He was fine last night before I went to bed no problems at all. Then this morning he was floating around the tank swimming very lethargically then just floating again. He died about 10 mins after me finding him like that. Can anybody help me? Is this common, and will it happen to my other fish?

 

[WILDER]

Size of tank in gallons or litres.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.

Bleeding beneath the skin is septicemia.
Plenty of water changes over the next few days.

Once septicemia progresses it hard to cure.
Causes of septicemia are, bad water quality, dirty tanks, cuts and wounds, parasites,etc.