So, over a year ago I set up and cycled a 10g tank, planning to house a betta and four panda cories. After it had cycled, I bought the cories and added them, then went to search for a betta I could move in after a QT period. He turned out to be too aggressive to the cories and I had to move him. I tried my two males at different times, and they were also too aggressive. Several months later, I bought another betta, tried him out, and sure enough, all he tried to do was chase and bite the poor cories.
Long story short, I love my cories and don't want to take the chance that they will get hurt, so I've decided to give up on trying to house a betta with them. I could just leave the four of them alone in their tank, but I'm thinking of adding another fish. Here's what I'm considering, which do you think would be best?
1) Dwarf Gourami--for those who have these fish, are they good with tankmates? Would I be able to QT one in a 5g tank for a couple weeks? (I know not everyone QTs their fish, but I really don't want to take a chance of anything happening to my cories). If so, would the tank need to be cycled?
2) A guppy--I don't know much about guppies; people seem to keep them in groups of three, but in such a small tank, I definitely wouldn't want babies! Could I keep one male guppy alone, or do they need to be kept in same-species groups?
3) Another panda cory or two--This is definitely my safest option, but it would be nice to have a "showpiece" fish in that tank, not to mention I'm not sure how to go about quarantining one or two cories. What size QT tank would they need? I assume it would need to be cycled? Would they be stressed without more cories to shoal with, or would they be ok since it'll only be for a week or two?