Tail Fin Damage In Tetras+ Update

[upsy daisy]

Hi,

I haven't posted on this forum forum for the longest time..

I have a 50l tank with 5 lemon tetras, 8 neon tetras and 4 albino glowlight tetras. Water statistics seem fine, all within normal ranges. I do water change every 1.5 weeks and change more than 50% of water.
Lemon tetras are the biggest of all and they have been in the tank only for about a month.

One of my neon tetras got sucked into the filter about 2 weeks ago, but I caught it soon enough and I liberated it. I noticed that all of its fins were damaged and ragged and it's body was slightly mis-shapen but it seems to be doing ok (is hungry and eating).

I kept waiting for it to re-grow it's tail fin but it seems that it keeps getting more ragged with each day, possibly waisting away. To my horror I realized yesterday that it might be a disease, as I noticed that another two fishes have a little bit of their tail fins missing as well.

I haven't really seen my fish nipping each other, they do chase ach other at times, but that's normal, right? What could be causing this tail damage and how could I treat my fish to make them better?

Thank you in advance!

PS I just wanted to add that my "raggedy" tetra's tail is half gone now, the lower half is not there anymore.

 

[fluttermoth]

Tetras can be quite nippy, especially in small groups, or it could be water quality; got any test results?

 

[upsy daisy]

PH - 6.0

Ammonia - noticed a slight elevation since the last test, perhaps 0.2 or 0.1

Nitrites - 0

Nitrates, noticed an elevation since the last time - 10


I have to say that my tetras have never nipped before.. The trouble is.. the tail fins do not look chewed off, they look frayed, unravelled, the tail looks raggedy.

Did a 70% waterchange today and added a fin rot medication, as I think it probably is fin rot. My poor, old, mis- shapen neon tetra is at the bottom now, but did gather its strength to go and feed.

I realize now what has happened. SInce I liberated my tetra from the waterfilter and it had been visibly been injured I started to feed my fish more for the sake of the sickly one ( because it is slower and cannot get to the food). So this now has altered the water chemistry and allowed for the bad bacteria to multiply. I will feed the fish less now, I just have to resign myself to the fact that I will lose the lilttle, injured neon.

 

[upsy daisy]

An update.

My mis-shapen, raggedy tail neon died. Same day I found (an externally healthy) lemon tetra caught and dead in the filter. It looked like it committed suicide..
I did a few waterchanges but today the ammonia was up again, even though I have been feeding fish very carefully (less amount wise).


Could the medication have affected the bacteria in the filter.. killed it off, I mean? I treated the tank with INTERPET Anti-Fungus and Finrot which contains Phenoxyethanol.