Black Tetra Getting Nipped Fins

[guitarplinker]

Hey everyone, I'm kind of a lurker to pet websites/fish advice, but I thought I would ask a question here.
 
Here's my current setup:
5 black tetras (4 young ones, less than a year old, 1 older one, 3+ years old)
3 peppered catfish (bottom feeders)
10 gallon tank
 
Anyway, I noticed today that one of the young black tetras has a chunk taken out of his top fin, probably 15% of the fin is gone. He swims a bit differently than the others, facing a bit upwards, like at a 20-30 degree angle upwards, and he is paddling much quicker than the other fish. I see the other fish in my tank chase each other around and nip each other I guess. What can I do to fix this? I did a 30% water change last week, changed the filter, and siphened (sorry not sure how to spell it, it's pronounced SEYE-FIN) the fish poop off the bottom of the tank. Any ideas of what I can do to help this fish out? Another fish or two have a bit of their bottom fin nipped out a bit, but nothing serious.

 

[eaglesaquarium]

Welcome to the forums!!!
 
 

Hey everyone, I'm kind of a lurker to pet websites/fish advice, but I thought I would ask a question here.
 
Here's my current setup:
5 black tetras (4 young ones, less than a year old, 1 older one, 3+ years old)
3 peppered catfish (bottom feeders)
10 gallon tank
 
Anyway, I noticed today that one of the young black tetras has a chunk taken out of his top fin, probably 15% of the fin is gone. He swims a bit differently than the others, facing a bit upwards, like at a 20-30 degree angle upwards, and he is paddling much quicker than the other fish. I see the other fish in my tank chase each other around and nip each other I guess. What can I do to fix this? I did a 30% water change last week, changed the filter, and siphened (sorry not sure how to spell it, it's pronounced SEYE-FIN) the fish poop off the bottom of the tank. Any ideas of what I can do to help this fish out? Another fish or two have a bit of their bottom fin nipped out a bit, but nothing serious.

 
 
That's the biggest issue you've got.  That tank isn't actually big enough for those fish.  The bigger the shoal, the less any individual gets picked on, and the more amiable they are in general.  Cories should be in groups of 6+ also.  You need at least a 20 to house these fish and up the numbers to the right levels.
 
Also, don't change the filters.  That's where the majority of your beneficial bacteria live and changing this will cause you to have ammonia/nitrite issues.