It's a 29 gallon tank. I have 5 gouramis, 1 Bala shark, 1 angel (which is in a 5 gallon quarantine tank at the moment) 2 tetras, and 1 that looks like a Bala shark but is colorful (don't know what he's called) I usually do a 25% water change once a week and I've never had any issues with the...