Aggressive Tropical Fish

[unprejudice]

Okay, Here is my problem. I just bought a new 55 gal Top Fin starter kit. My take was up and running, I added a small amount of fish food and water stuff to make my water safe, Let the tank run for 7 days before I added the first three fish. A week later and after a 10-25% water change, I added another three red tetra (I think that's what they are). A week later and another 10-25% water change I added three oh the black skirt tetra (I think that's what that is) I came home yesterday to one of my red tetra dead. I removed him from the tank and went to bed. I woke up this morning and my red tetras have became every aggressive with there own kind. My three black skirt are holding there own and are not being botherd. I have been checking all my levels and my ammonia was getting a little high but I bought some stuff to add to my filter that removes the ammonia from the tank and plan on getting my levels tested again today. Other then that my tank is set up in a 55 gal tank (it wont let me upload pics) I have river rocks in the bottom, plastic plants and a big aquarium log in the middle. (will be going to live plans soon but need to upgrade my lights so they will help my plants grow bigger and faster) I added a tad bit of stress coat and some food to the tank, and it seems to have calmed down a bit but still have a little nipping going on. I'm not sure what to do. ;\

Tank size:55 gal
pH: I'm sorry I don't have one yet, last test was 5 days ago
ammonia:I'm sorry I don't have one yet, last test was 5 days ago it was a little high but I bought some stones I added to lower it
nitrite: good levels
nitrate:good levels
kH: ?
gH:?
tank temp:78-80

Fish Symptoms (include full description including lesion, color, location, fish behavior):
chasing around the tank, nipping fins, high energy

Volume and Frequency of water changes:
10-25% once a week
Chemical Additives or Media in your tank:
PRIME, Stress coat

Tank inhabitants: Black skirt tetra, red tetra.


Recent additions to your tank (living or decoration):
Just started adding fish, after 7 day empty cycle after adding small ammmout of food, 3 fish per week
Exposure to chemicals:
None I dont think?

 

[AquaticRex]

i think its a territorial display. I'm not 100% on my theory so don't base it on my words. i had some black phantoms and they usually displayed a sort of charging at each other. i don't know if that's what yours are doing but usually that should be harmless, unless they are actually biting at each other...