i reranged the tank yesterday so its clean as a whistle. now the knife has a shady spot, the gouramis have the log to themselves, and the goldfish can nap cofortably
ok, those knife fish reach an adult length of over a foot long, the goldfish you have can reach a foot long in a year.
honestly, if you can't see that the pet stores are only interested in selling you as many fish as they can, there is no help for you.
think about it...if you listen to us, you buy less fish, less medicines (your fish will be healthier), less fish food. If you listen to them, you will have more fish die, you will buy more fish, constantly be buying fish medicines, fish food etc.
once you have a better grasp of what you are doing you can overstock a little by having a water test kit ( not just strips, a real deal kit), knowing the signs of stress (your goldfish aren't "napping", they cant get enough oxygen!), stocking live plants (these help your water if you know how to care for them) and in general not having your head up your ass.