i have a 20 long has been up and running a little over a year. i have 5 red serpae, 5 bs tetra , 2 otto , i g. blue ram, and one emerald cory. i had 2 cory but lost one this was the only fish i have lost yet. i didn't notice any difference in the solo cory. he was as active as ever. if you have room and when your tanks water parameters are very stable. try a ram. this fish has more personalty than the rest combined. mine watches me and is always front and center to show off. java fern will flourish in this tank with standard lighting . the tank is not very deep. i just use flora pride fertilizer with w/changes. i use an aqua clear 50. on one end and a whisper submersible 10 on the other keeps mine crystal clear with minimal effort. i like the long tanks, and am itching for a 40 long next. if you go with 2 filters just dont change both media at same time.