Hello everyone, I've gotten myself in a bit of a pickle as far as fish stocking goes. I work at a pet store, and a few weeks ago I had the displeasure of someone abandoning fish. They had 2 black skirt tetras and 2 peppered corys, and when told we could not take them, plunked them down on a counter and left 
To keep a longer story short we couldn't keep them in the store, so I took them home and added them to my 20 gallon tank. One of the peppered corys died a week later (had damaged fins), but the rest are still doing good. Now that exams are over, I want to focus on getting this situation straightened out so that all of the fish are happy, but I fear that would involve over stocking my tank. Said 20 gallon now contains:
-3 black skirt tetras (one of them is over 4 years old, I was just planning on letting him die off)
-5 glow light tetras
-3 male guppies
-2 zebra danios (also over 4 years old, am just planning to let them die off)
-3 bronze corys
-1 peppered cory
-3 nerite snails
So ideally I would need to add 2-3 more black skirt tetras, 1 more bronze cory, and 3 more peppered corys, which to me is way too much. I'm in the process of setting up the aqueon 30 filter (rated up to 45 gallons) to help out, and am cycling a 10 gallon to move the guppies into. I cant buy a larger tank, there's nowhere practical in my home to place it. So considering the fact that I will soon have a 10 gallon to work with as well, is there any way I could make this work? Or do I need to sell some fish? Also, I'm not a massive fan of black skirt tetras, they seem too large for a 20 gallon, would it be cruel to just leave the three alone until they die?
To keep a longer story short we couldn't keep them in the store, so I took them home and added them to my 20 gallon tank. One of the peppered corys died a week later (had damaged fins), but the rest are still doing good. Now that exams are over, I want to focus on getting this situation straightened out so that all of the fish are happy, but I fear that would involve over stocking my tank. Said 20 gallon now contains: -3 black skirt tetras (one of them is over 4 years old, I was just planning on letting him die off)
-5 glow light tetras
-3 male guppies
-2 zebra danios (also over 4 years old, am just planning to let them die off)
-3 bronze corys
-1 peppered cory
-3 nerite snails
So ideally I would need to add 2-3 more black skirt tetras, 1 more bronze cory, and 3 more peppered corys, which to me is way too much. I'm in the process of setting up the aqueon 30 filter (rated up to 45 gallons) to help out, and am cycling a 10 gallon to move the guppies into. I cant buy a larger tank, there's nowhere practical in my home to place it. So considering the fact that I will soon have a 10 gallon to work with as well, is there any way I could make this work? Or do I need to sell some fish? Also, I'm not a massive fan of black skirt tetras, they seem too large for a 20 gallon, would it be cruel to just leave the three alone until they die?
