a newbie needing help

[spirit_level]

I have tropical Biorb tank :

Alls been well up till yesterday. We decided to go out and buy some fish. We already have 4 Zebra Danios in and they have been fine. We took a sample of the water with us to check for ph levels and the like at the pet store said that everything was fine. We decided to buy 3 Neon tetras. Now everything was fine until i went to bed last night and noticed that one of them was swimming funny (basically on it's back) I rang my boyfeind at work and he said to leave it and he wouldsort it out in the morning when he came in from work. When he came in he had to remove 2 of the 3 as they had died during the night.

I have just had a look at the one that is left and it looks ok but every so often the zebra danios will barge in to it and knock it about. Have i just got a bad batch of fish or are Zebra danios jsut bullys and have they killed the other ones?

 

[Angry_Platy]

Danios can be bullies and neons can be fairly fragile.

Did you cycle the tank? Did you use fish to cycle the tank??

I can't imagine the danios would have killed the other 2 fish though....WEIRD....

What exactly did the LFS check for in your water? Did they tell you?

Chances are the neons that you got were sick to start with.

 

[Inchworm]

Hi spirit_level

Welcome to the forum.

It sounds like you are new to fishkeeping as well. If this is the case, there is a little science involved that you should learn. It's not too complicated and once you have a bit of basic knowledge about what is going on behind the scenes of a healthy tank, it will be much easier to understand what is happening to your fish.

For starters I would suggest that you read this article about cycling a tank:

http/www.fishforums.net/index.php?showtopic=10099

For now, how big is your tank? What is the water temperature? How long has it been running? When you had your water tested at the lfs, did they tell you anything else in addition to pH? Specifically, we would like to know about readings for ammonia, nitrIte and nitrAte levels.

If you add your location to your profile, it will also make it possible for us to give you advice about medications should it be necessary.

 

[The-Wolf]

Hi
Zebra danios can be very very aggressive if kept in the wrong conditions. IMHO a biorb is way too small to keep ZD's in.
Their aggression will get greater the longer they are kept in there, to a point where only one will be left because all other fish will be killed by them and then they turn on each other.
You can read about ZD's on my website.