Quote Originally Posted by andreahp
Hate to say it - LFS's are famous for telling people their water parameters are FINE - even people who just set up their tank 1 hr ago and haven't put fish in yet - they will have readings of all 0's (which is an uncycled tank). I haven't read all the posts in this thread yet but has anyone suggested you getting your own liquid test kit so you don't have to keep bringing water samples with you?

How do you know for sure your tank was cycled? Did you ask the LFS what the readings were? They should be able to tell you you have no ammonia, no nitrites & 20ppm or less nitates unless their strips aren't that accurate. Also, many fish stores (my local ones included) will tell you that an ammonia level of up to 1.0ppm is FINE - it isn't!!
I agree, you have no way of knowing for sure what your water parameters are when having a store test your water. nitrates of .5 are very unlikely.

Lack of o2 for that stock is very unlikely as well. These fish are some of the more resilient when it comes to o2 levels. Did you ever use any Melefix? because that can suffocate all of those fish.