Hi, I'm a novice to fish keeper who decided to buy her first betta tank a month ago. My mother use to keep fresh water tropical fish when she was a girl and I had been toying with the idea for a while and on the advise of my mother decided to start with betta. on the 24th of May I purchases my tank from 'Pets at home' which is a large pet store here in the uk. The equipment and decorations I purchased where on the advise of the girl serving there. The tank itself is a split 20 lt with heater and filter and a simple led lamp on top. I decorated this with gravel, pebbles and silk plants all brought from the store. I have recently purchased a perspex tube which I cut in half and have been using to form a sort of cave with the pebbles. This however is a very recent addition after the start of my woes Photos: Tank: Filter: After 8 days of running the tank with treated water I purchases my first betta (Iccy) from a breeder. I added the quick start and everything was going fine. 5 days after I purchased my second betta (Carl) from the same breeder and places him in the second half of the tank. On the advise of the breeder I also added 1 level tsp of aquarium salt (dissolved) and half an Indian almond leaf to the tank. All was well for a further 4 days then I decided to do a 25% water change using 2 2lt bottles of treated water I was keeping to the side. The day after I noticed tears in Iccy's fins and could not find the cause of. I asked a friend who also keeps fish as well as the pet shop expert who both seemed to agree it looked like they had been nipped. Odd for a fish who was alone in his half of the tank. I could not work out what had changed since the water change but assumed that maybe I had increased the water level in the tank and my other betta, Carl, was somehow nipping Iccy's fins through the slits in the top the the tank. But even after reducing the water level, Iccy's fins just seem to be getting worse. Here is picture of Iccy. On the left was when I got him, the middle was the day after the water change and the third is how his fins looked today. Iccy: Carl on the other hand looks just the same as ever (left when he arrives, right was taken today): Carl: I took both fish out of the tank and gave it a complete clean before added them again (the water didn't seem to be too bad when I tested it but I thought this would be the safest thing to do. However the following day his fins seem to have gotten worse! I have today removed Iccy from the tank and made a make-shift tank for him out of a large, clean, preserves jar and a mini heater with fresh treated water: I have also added some of the following to the water: This is how the water tested today thought I doubt there would have been anything wrong as the tank had just been cleaned and will need cycling again: Someone thought the problem may be the gravel in the tank which seems quite course. I have purchases some large gravel to replace it if this seems advisable: Others: Products I've also been using: I feed these boys on daily live white mosquito larvae. The flakes I started with but they were not really eating it (spoilt boys!) and the freeze dried blood worms I only give them now and then like after their water change (I felt so guilty!). If any of you have any advise of how I can help my poor Iccy I would really appreciate it! Despite his troubles he is still really lively and as greedy as ever. Could someone also let me know if I will ever get his fins back to their past glamour? Thanks for reading.