okay.. i have a 20 gal. i have a nickel size angelfish already, just got 2 more today they are only 2 mths old so very small still, and i also have a smaller bala shark along with my smaller pleco. i have 2 hiding spots for my tank, i have i have 4 sm-md plants. some are put together to form what i call an adequate angelfish hiding spot. others along the sides of the back just for my liking. i have no problems with my water ever. thank god! i make sure my tank is top shape. its very important to me to ensure that my fish are comfortable. Ive had mixed reviews on balas and angels, but mine doesnt really bother anyone else. I just want to know answers from ppl with experence with tanks. Can i have any more of different kinds of fish to go with what i have? Oh btw i figured id let you know to save your breath that im goin to remove some of my plants and 1 of my hiding spots to make sure there is enough space for swimming, but they have never seemed stressed about it. If you know anything useful please share it!! my mind is always open on your experience for the better of your fish!!