Longfin leopard white on top fin

My longfin leopard has white on the back end of its top fin. I cant say its something ive noticed before. Could it be due to doing a lot of water changes for ammonia? Stress. Is it just normal fin growth?

It will be impossible get a picture as hes a fast bugger! Hes eating normal and chasing the females about as normal. He is the only longfin danio I have. Some of the other danios have a white border around the top fin but the leopard seems to have more white than the rest

I managed to get some pictures