Hello, my male betta Valentino has been tail biting for a while, although I noticed that he now has black on the tips of his fins,therefore I assume it can be finrot now. Is it? I haven't tested my water but I will get a test kit ASAP (unfortunately the pet store I went to was out of stock when I tried buying one yesterday). The tank is 4 gallons(uncycled). I do one 80-90% water change and one 50% water change each week. It has no filter right now, the filter stopped functioning about a month ago. The tank is, of course, heated.
Sorry for the poor quality picture
A bad phone camera+camera shy betta= bad pictures