I would not say to remove the plants. The plants will give them places to hide and keep down the stress. If you can even, go out and get a 10 gallon tank. They are not very expensive and will add some more space for your fish. You should be able to use most of the decor from the 5 gallon in the 10 gallon tank. I live in Wisconsin USA and a 10 gallon tank is about $10US at my local Wal-Mart. You should see a big difference in the fish with a bigger tank.