Survival of the Fittest?
 

I'm trying to establish a school of 6-8 neon/cardinal tetras in a 10 gallon tank. Through attition, I currently have 2 neons and 1 cardinal. Whenever I try to add new fish, the next morning the tiny newbies are dead. It's obvious that they are picking on the new fish. What can be done about this? Different type of tetra that is a bit bigger?

Thanks.

How long has your aquarium been running?

What are the parameters? ammonia/nitrite/nitrate/ph/temp

what is the hardness of your water?

If you can let us know these, we may be able to help you with your problem. :)

Also can you describe in detail how you add the fish to your tank. This has an effect also!! Sorry to hear of your troubles. What type of filter are you using too? Thanks
Hoping we can help you sort this out.

Thanks for everyone's quick replies! My parameters are:

0 Ammonia
0 Nitrites
5 ppm nitrates
6.8 ph
78 degrees water temp
30 gh
about 20 kh

I've got an Aqueon 20 filter

I did a fishless cycle, and then added cardinals/neons 2 at a time, once a week...I do 25% water changes once a week, and its been running for 3 months in total.

Thanks in advance!

Just from a quick glance at the profiles for Neon Tetra and Cardinal Tetra, the cardinals need a much lower pH. Less than 6.0, so this might be your problem with the cardinals.

Another thing you might try is rather than adding just 2 at a time, add 4 or 5.

If your tank is cycled, you should be able to add several neon tetras at a time. This will help the neon's cope with the stress of the move much better. Also they will be more stressed in groups smaller than 6 or so. This will make them more susceptible to disease and it could be your problem.

Thanks Jbro...just for my own knowledge, what fish would be good for my size tank and water parametes?

There are several smaller species you could do in your tank.

Some off the top of my head are:

Mosquito Rasbora
Dwarf Rasbora
Ember Tetra
Neon Tetra
Dwarf Cory's

Just take a look at the fish profiles up in the top left corner on the blue bar. You can search through there to find some species that will fit your tank.

In my opinion that tank is to small for many tetras. But Jbro has suggested some good candidates

So here's the next chapter..I went to my LFS to explain the situation. Now this is all from them...they told me that if I added more neons, they probably wouldn't school with the ones already in the tank. So they suggested head and tail light tetras. So I went home with 5. Acclimated them to ph and temperature properly...woke up this morning and they were all dead. With fins that were shredded. Is it possible to have neons/cardinals that are so aggressive they won't allow any other fish in the tank? Any suggestions?

Thanks in advance...

I dont think your LFS knows that they're talking about. =/

This is true in the case of angel fish.

But I've NEVER had any characins that wouldnt "shoal" together. Even if added separately.