ahursh142

I recently started a new aquarium (about 2 months ago) after I let the tank cyle, I added 3 zebra danios because my boyfriend said they were a good starter-fish. after 2 weeks putting those 3 in, I went and bought 3 more because I know they are supposed to be in a school of 6 or more. The very next day, I noticed one of the newbies was swimming funny and had red on his side, as if he had been beaten up. That evening, he died. Then another one died, then another! the 3 new fish all got killed! I'm convinced that my other ones killed those 3 new danios! They all had the same symptoms. They looked beaten up, swimming funny, and hiding. I realize that new fish are subject to stress, which explains some hiding, and I'm pretty sure I waited long enough for the tank to settle before adding the extra 3.. so what happened? They chase eachother around now, but for the most part they get along. I'm just nervous to go out and get 3 more if they will just kill those ones too, but is it ok the just keep the 3? and also.. what other fish would go well with my serial killer fish?

Tony G.

Welcome to Fishlore!
sorry your fish are going through some trouble
So, it says on your aquarium info that you do not know about the nitrogen cycle.
here is a helpful link that will help you learn about it!
http://www.fishlore.com/NitrogenCycle.htm
Also, it says that your aquarium is a 10 gallon. IMO your tank is fully stocked, so you wont be able to add anymore fish.
What are your water readings for ammonia nitrite nitrate and pH?
Redness on the gills on fish is a sign of ammonia poisoning which can lead them to death. Ammonia is toxic to fish and so are nitrites, however, nitrates arent toxic to fish in low levels ( below 15 PPM )
We also reccomend you get your own personal freshwater aquarium test kit. Some members really reccomend the API master test kit. I have used it and it works great! there are some other brands like Nutrafin's test kit that is also pretty good. Make sure it is a LIQUID test kit, not a strip one as they tend to give false readings...
sorry for all the info! hope i didnt scare ya

iloveengl

Welcome to FishLore!!

I second Tony 100%.

Those symptoms sound exactly like ammonia poisoning. You may want to complete a 70% water change (add water conditioner) asap to temporarily remove the ammonia (caused by fish waste and over feeding).

Then, as you are reading up on the nitrogen cycle that Tony linked for ya, I would recommend buying a bottle of Prime and use it in conjunction with daily partial water changes 30-40%.

Danios always chase each other around and this is normal. If they are being more aggressive than that, it's likely caused by the stress of the poor water... any fish will act this way.

Once you get those water changes going, your fish will be feeling WAY better and you can start to enjoy them with less worry.

heather84

I had danios and they were mean.....they killed 2 of my neons and a few other fish

we eventually got rid of them. But mine laid eggs like crazzzzzzzzy so im not sure if they were overly agressive because of being pregnant or what.

Tony G.

True, that could be a possibility.
But i think the Ammonia poisoning would be the culprit....

DeanAsploded

Whenever you add new danios it throws off the dominance order, and it has to be re-established, occasionally resulting in injuries bad enough for death. Three at the same time, though? Doesn't seem plausible. Buy a test kit, I'd suggest.

peacemaker92

WELCOME TO FISHLORE!

I don't have much to add, everyone's got you covered Good luck!

ahursh142

hey guys thanks for all the info.. but they weren't red on the gills, it was more like on the back by the tail..

Shawnie

welcome to fishlore!! and sorry for your losses
do you know what your ammonia/nitrites/nitrates are? any red on a fish could be ammonia poisoning...ammonia bursts blood vessels in fish and even on the tail area could show up..but if there was any ammonia in the tank , and the new babies added werent use to it, it would weaken them and a weak fish, is always picked on .....the danios you have could be somewhat use to the water parimeters so testing asap is a must ....