Hi , friends\nI’m Neha\n\nI am having an aquarium tank with 5 fishes in which two of them are koi fish and two are gold fish and a black eye fish . the black eye fish has some tiny black small lines [ since last 1 month] in some parts of her fin which now has spread through to her body as well and i have tried some medicines like BACTONIL FW and GRANDFISH WHITE SPOT CURE but not got any successful results .all fishes are OK except one koi fish which has clamped fins and one goldfish with torn fin / tail . Since i have only 1 year experience with fishes i don't know what to do .i don't have any special equipment like water test kit .please kindly suggest me some remedies so that i can cure it .And how much time will it take to disappear from my fish?\n\ntank is of 25 liters\nthe black eye fish is of 4 inch or10.6 cm [approximately]\n I don’t know whether my filter is biofilter or any other and if is then I even don’t know the level\nthe fishes get oxygen through the filter itself so there is no need of air pump\n\n some days before I also noticed red streaks on her fins [back fins] and have separated her in a tub with an air pump [flow rate i don’t know] and has tried a new medicine called PARACIDOL FW for only two hours and now she is again in her tank. She always sits on the stones and is not much active but will be when its food time.\n\nthe black eye fish is jumping out of water[not falling down on floor ] again and again since last month . and so i used to change the water from the tank after every 2 weeks and used to add aquarium salt . But now it has been a month but no improvement is seen . please kindly suggest something .\n\nalso today I saw the two goldfish and the black eye fish have red and torn fins [ all the fins are almost torn] so I added the medicine again BACTONIL FW as it has once cured my koi fish at the time of fin rot.\n\nSo I did 100 % water change[ full tank and gravels ] but have not added any medicine in the tank just aquarium salt .