My bettas recently had torn fins from other reasons than a filter problem..(I don't have any filters) Melax does help the fins get repaired . you might have to do some math to figure out how much to use in your tank. Since I keep my bettas in tanks with about 1 pint of water each I used 1 mL or 1 cc of melax everyday for 7 days . after that I did the partial water change like the directions on the bottle said. Basically I recommend you use melafix to help your betta get his fins grown back.