My sorority fell apart.

[LadyVictorian]

Yeah either it was an ammonia spike or possibly the two new girls on or both brought something in with them. I'm sorry to hear this happened. I hope you can get what fish survived healthy again and start over.

[callistra]

Mystery snails are really really dirty and ammonia would grow quickly even with just one. I think that many betta and 3 snails in a 10g is a heavy bioload. Probably had some spike in the tank.

While you are cycling a tank you need to test daily for ammonia and nitrite and do a 50% change any time you see as little as .25ppm. You may always have to do a larger weekly change or a couple changes a week with that many fish and snails, but especially while you're cycling it's important to monitor closely. one weekly change will not be enough.

Very sorry you lost them :(