ammonia burn?

[haleybeth30]

I know it's hard to see in pics but I've noticed darkened fin edges. I will say I changed one of my bulbs, but that should't matter, although makes their blue really shines.. Anyway, my tank has been up about mo. and a half, fish in cycle, about 2 wks ago started getting 0 nitrites and 0 ammonia. I haven't tested nitrates. I just tested ammo and trites, both zero. The water has been good for a while, don't understand why effects would show now.. Also, changed water close to daily with prime, ran out of prime couple/few wks. ago been using jungle start right.. Could this be the reason I'm seeing it now even though tank parameters good? What else could cause darkened fin edges? What can I do for them? As a side note I have peacocks in another tank, O in another tank, sevs in another tank and this isn't happening with them...
thanks

 

[haleybeth30]

better pics, I hops