Hi, I'm seeking any help please in regards to my goldfish who has red lines through his tail and also what looks to be small growths on his dorsal fin. He hasn't lost his appetite but sometimes is floating at the top of the tank. I've had him for around 4 years. He has been set up in this particular tank for 3 years with no problems. The tank is 42L and he is the only fish thats ever lived in this tank (purchased new) I just have gravel on the bottom (i did have fake plants but have removed them some time ago) I use a gravel vacuum about once a month and also do 1/4 water changes every 1-2 months.