Fin Rot or Nipping or Neon Tetra Disease

[AquaAggie]

Ok so I have a 60g that’s been up and running for a year. 
 

water parameters:

• pH - 7.9
• Nitrates - 20
• Hardness - 7.5
• Nitrite -0
• Ammonia - 0
• KH/Buffer - 5
• Water Temperature - 79

inhabitants:

11 neon tetra (been in tank whole time)
1 pearl gourami (10 months)
M and F apisto caucatoides (6 months)
3 sterbi cories (1 year)
5 khuli loaches (1 year)
1 super red bristlenose pleco (1 year)
2 Bolivian rams (10 months)
1 silver hatchet fish (10 months)
1 pearl scale marble angel (3 months)
4 golden wonder killi (1 month)
nerite snails, MTS, Amani shrimp

Over the last month to six weeks I’ve noticed my neon tetra school’s tails looking pretty beat up too nearly missing. At first it was just one that looked really bad and almost like tumor or a wound at the end of the tail before it forked out  when I was ready to pull him and medicate it started looking better and the tail had started growing back. There is still a bump and tail is not all back but doesn’t seem bothered.  But now there are maybe 5 with beaten up tails.  they still look ok otherwise, are eating, schooling and swimming relatively ok.  I don’t see anyone chasing anybody around or nipping at anyone  the Bolivians will half-heartedly spar sometimes, the bristlenose will chase anyone away from his piece of food, and the female apisto is cranky even though she and the Male pay little attention to each other and she mostly goes after the gourami or angel if they invade her part of the tank for the day.

I tried to take pictures but funny enough neon tetras don’t want to stay still for pictures.

Is it fin rot, NTD, or fin nipping? How do I tell the difference?  Should I just do a full course of maracyn on the whole tank?  Thanks

 

 

 

[Colu]

Symptoms for neon tetra disease loss of colour bent or curved spines  and cyst in the muscles if they have not had any of the these symptoms it not neon tetra disease