I got my 36 gallon tank for Christmas and got it set up with water decor and plants and filters oh my! After a few days, I added cats. (Really literally, it's like TV for cats!) Oh, and two loaches and corydoras. The water conditions didn't seem to change so presently I added some tetras. With still pristine water, several of them didn't make it. I will note that as the store girl was chasing them down I was tempted to ask for the net so I could just do it myself, a couple of them looked stunned. Probably the ones that didn't make it.
And after a while more, the bettas. The two blues I got promptly developed what looked like the blue betta sickness during QT. The teal...I think she got hold of part of an algea pellet that was in the bottom for the pencil suckerfish after I added her. Did not end well

No more pellets. A multicolor...not sure what happened to her but found her on the filter intake. She has damage to her lip. I didn't see anyone chasing her, so I'm not sure what happened. She's recovering in a tank with IAL and stresscoat. She can't manage the Hikari beta pellets, but she can eat the micro pellets and seems to be regaining strength. I'm hoping her lip will heal, but I really don't have experience with that kind of injury and I'm just taking it day by day. Since she made it through those first couple days, I'm cautiously optimistic for her. And last but not least, the mercy buy, a scrawny looking see through stripey juvenile with SBD is doing GREAT in the little tank I put her in to de-cup. She's colored in wonderfully and the stripes have gotten much less pronounced. I think she gets another couple of weeks to just grow a bit.
And in the tank, the proto-sorority of the three healthy ones is getting along really well! They come up to the top together to get fed (which causes the tetras to also swarm up to the front since they know it'll be their turn soon). The loaches are even getting wise to this, they squiggle up to the top too to try to snag food.
Rough start, but really shaping up now. And it's better than HBO for our kitties.