betta(halfmoon) died asking how

[arima moua]

one day he was laying on the floor of the tank then on the top same spot he was still alive then wen i came back from school it was dead on the bottomjavascript:emoticon('')

[Flashygrrl]

Tank size?
Water temp?
Heater used?
Water change schedule?
Water change amount?
Water parameters (ammonia, nitrite, nitrates)?
Feeding schedule?
Any other occupants in the tank?

All of this is important to know.