Those type of fish will acclimate just fine to almost any water, and in fact I've never seen dropping them directly into new water cause them to die (and tons of people do this when they stock ponds).
So it's pretty obvious that you had an ammonia spike or something (was the tank cycled?).
I don't know what you mean by your params were perfect. What were your ammonia, nitrite, nitrate and pH levels, and do you know for a fact that your water is well buffered and doesn't have pH swings?
So it's pretty obvious that you had an ammonia spike or something (was the tank cycled?).
I don't know what you mean by your params were perfect. What were your ammonia, nitrite, nitrate and pH levels, and do you know for a fact that your water is well buffered and doesn't have pH swings?