I'm a beginner and I bought my tank with fish in it added a few more and fish are dying everyday. I haven't checked levels yet due to not having testing supplies right now. I plan on getting them in a few days. So It started out with 2pleco 2corie 4glo tetras 2dojo loaches (i think) a male Betta and 4 frogs, one got smooshed on the drive over so 3 ADF. I bought one more frog to replace the smooshed one and another yo-yo loach (not knowing I had dojo loaches) and 2 more tetras. About a week later I added 2 albino Corie 2 more frogs and a gold skirt tetra.. things were fine, then all of a sudden I brought home a second hand rock because I badly wanted a big rock that I could never afford. So, my Betta 2 frogs an albino Corie and a peppered Corie (I think) dead, and oddly enough 3 frogs beat up bad. I flipped, took out the second hand rock and scrubbed the tank and decorations, separated the frogs (because they are my fav) treated the tap water and added my fish now a little go tetra is swimming sideways and he's been forced under a rock for a few days before this.. any advice would be highly appreciated I'm worried I'll wake everyday to a new death