lets see here is a very small portion of my list
1. let the guy who was sleeping on the couch wash the filter cartridge in the tap water daily for about 3 weeks before I did some reading
2. put a baby bichir in a community/breeding tank(50 platys gone in 2 weeks)
3. moved that bichir to his own tank and got him some extra large Giant river prawns(7" body 16" with claws) the bichir was 3". I found him the next morning with no head
eventually I learned the 3 main things in fish keeping research, research, research