I have a betta, fancy goldfish, and dwarf gourami. I used to house my King Betta in a 10 gallon tank, but due to abrupt complications he is now housed in a spare 5 gallon tank I had on hand. My dwarf gourami is residing in a 10 gallon tank, but I’m pretty sure they need 20 gallons. My fancy goldfish is in a 20 gallon, which I believe that’s okay. My problem is that I am aware that both my betta and dwarf gourami are in tanks that are too small, but my parents refuse to let me get a larger tank, even though I have a job. I do however do a 50% water change every week and check the parameters using the API master test kit. I am also planning on designing fully planted tanks for all of my fish. I am wondering, are these tanks simply too cruel, or is it okay that they are in smaller tanks then needed?? I am not worried about ammonia buildup or anything as such, I am just worried about the actual size of the tanks. Can anyone help??