Fin Rot - Newbie Style

[sizzla01]

Since adding 5 red eyed tetras (last Saturday) to my 70L month old tank, that already contains 6 danio’s.

I noticed (on Monday) that 1 of my red eye’s had developed partial fin loss to the anal and tails fins leaving them Jagged. Then yesterday I noticed the same has happened to 2 of my danio’s along with slight whitening to the fin edges of 2 further danio’s.

From reading the emergencies section it sounds like I have a case of “Fin Rotâ€￾.

Are these classic signs of Fin Rot ?
Is this fatal ?
What is the best approach in treating this ? both procedural & products to use/buy

My last water change was Saturday (20%) just prior to the introduction of the red eyes and my last readings were 0 ammonia, 0 nitrate, 25 nitrate.

Any advice welcome

 

[Betta91]

It doesn't sound like fin rot to me, but I really can't tell unless I have pictures. If you have Danios in there, it's a very good chance that they nipped the fins of your other fish. Danios are known for their somewhat aggressive behavior, so I wouldn't be surprised if they got a hold of your Tetras