Any ideas what this could be?

[nicbmik]

Black on tips of fins. It's causing the molly to take long rests on bottom of the tank. Nitrite/ammonia levels are normal; no other fish are affected. Help?

 

[GNarnian]

Hmmm, usually when fin tips turn black, it's from ammonia burns. Are you sure ammonia is at 0?

 

[BBradbury]

Your Molly

Black on tips of fins. It's causing the molly to take long rests on bottom of the tank. Nitrite/ammonia levels are normal; no other fish are affected. Help?

View attachment 233653

Hello nic...

Does your Molly have a bit of salt in its water? Mollies are essentially brackish water fish. Their bodies are designed to benefit from water with a trace of salt in it.

B

 

[nicbmik]

Ammonia is consistently 0- I usually check weekly. Water is slightly brackish- I have some neons so I can't have too much salt. I have two other mollies and neither is having the same issues.

 

[Delapool]

How's he doing? I was wondering if it could be natural colour or did it change fairly quickly?