Sick Molly

[Sam87]

Hi I'm new to this. Bought a 125L tank about 3 months ago. We bought 5 mollys a few weeks ago, 2 have died and 1 isn't well. When it isn't swimming it is lay on the bottom on it's side and when it is swimming it is vertical with it's tail pointing straight down. Any help thanks

 

[WILDER]

What are you water stats in ammonia, nitrite, nitrate, and ph.
If you are only thinking of keeping mollies they do better in brackish water.

What do you feed the fish.
Does the fish look bloated.
Does the tail of the fish looks like it weighing the fish down in the water.
It sounds bacterial to me.