Take your time, research, read, think about it, reconsider, research some more, then go to the store.
green terror, oscar, jack dempsey, frontosa, convict, skat, var. puffers, mono, white tip shark, var. pleco, labs, neon tetra, cardinal tetra, discus, betta splendin, serpae tetra, mollies, pictus cat, otocinclus, blood fin tetra, cory cat, and anything else I forgot to mention.
To many to mention, all plant tanks running DIY Co2 systems.
fish don't need toys, get that crap outta the tank!
Dealing with pests is an inescapable part of cultivating a marine tank.
Proper filtration is the key to keeping your freshwater aquarium healthy.
Cultivating a nano reef tank can be an exciting challenge.