I'd like to get some opinions on how many more (if any fish) I can responsibly put in my tank. I have a 55 gallon(standard dimensions) planted tank with a Whisper PF-60 HOB and two airstones. I perform a 20% water change every 3-4 days. With my current stock my Ammonia and Nitrites stay at 0 and my Nitrates don't get above 20. Right now I have an African Butterfly Fish, a Dwarf Gourami, an Angel Fish, 5 Glass Catfish, 3 Yo-yo Loaches and 8 Harlequin Rasboras. I would like to add a few more fish, but I would like opinions on how close to my maximum responsible stocking level I am. I wouldn't mind adding more/different filtration if it would increase the number of happy fish I could have. Thanks!