Danios and Fighting Fish :(

[t0ny84]

Hi all I am hoping someone might be able to shed some light on what might have happened to my Danios.

Back Story
I had 2 Danios which were in with 2 Goldfish. The tank they were in had an algae bloom / green water.
When I changed the water / got this corrected I put the 2 Danios in another tank by themselves. They were happy swimming and all was well in the world.
2 weeks ago I purchased a Fighter Fish and he was added to the tank with the Danios. They (looked) happy together and there was no aggression from anyone of them.
Fast forward to last night I came home from work and one of the Danios was on the bottom (assumed) dead. Wasn't able to remove him last night so when I got home from work today I went to get him out and found the other Danio was floating dead. I took him out and when I took the other Danio out he was gasping for air. I put him in a fighter fish tank with some fresh water.
The Fighter Fish is still swimming around and looks to be ok and happy.

I know I should have quarentined the Fighting Fish but don't believe that adding him has caused the two Danios to die.

If a fish is carrying some sort of bacteria or issue is it normal that it could take 2 weeks to see any ill effects on the other fish?

Thanks for any guidance and for reading this long winded post.

 

[t0ny84]

Forgot to include:
Food - flake fish food.
Tank setup about 1 month
Small clip on filter
Unfortunately don't have a kit to test my water parameters at the moment.

Because the Danios have been happy and the fighting fish is still happy I don't believe it's water quality.

I have just never had a fish go from swimming to dead in less than 24 hours.

 

[King Fisher]

I'd say your tank probably isn't cycled due to the little amount of time you've had it. There's a good chance you are getting spikes in water parameters from the unstable water. This could cause sudden deaths. But you also put a Betta in with them which he could have very well attacked them. Male Bettas have a hard time being kept with even female Bettas at times let alone other fish.

My suggestion would be to get the Betta a 3-5 gallon tank for himself or keep him in it's current tank by himself if the danios are deceased. Being that the tank probably isn't cycled.....start doing 25% daily to every other day water changes until you can get an API master freshwater test kit. The kit will give you a gauge on when you will need to do a water change and how much to change.

Some fish are tougher than others and react worse to poor water conditions. Some will act and eat normal then develop fin rot all of a sudden from ammonia..... there's several scenarios.

 

[t0ny84]

Hi King Fisher, thanks for your input. the tank had been setup for about a month before I added the beta. I am thinking something to do with water but as they seemed content and happy 1 day then dead the next made me think it could be something caused by the beta E.g. it has brought in sickness. But then he is ok. Grrr
I am going to do a water test on the weekend and hopefully this will help answer it.

Never saw aggression from the beta except towards his reflection!

 

[King Fisher]

Typically a cycle takes 6-8 weeks. Depending on how you cycled it can be earlier or take longer. Testing ammonia, nitrites and nitrates will give you a good idea if it is or not. Bettas are pretty unpredictable IME.

Do the danios have signs of fin damage, Gill damage, scale damage or discoloration?

 

[t0ny84]

No damage just look like they're sleeping.

 

[t0ny84]

Actually just had a closer look at the Danio which is still alive. His tail fin is damaged and his body appears slightly bent. I know that the deceased Dano used to chase it around before I added the fighting fish. I never saw any aggression from any of them but thought that the chasing was dueto wanting to mate.

 

[King Fisher]

If his body or spine is bent and he's not eating there's a good chance he may have TB

 

[t0ny84]

Hi King Fisher, I have decided to put it down to bullying by most likely the beta. It makes the most logical sense.

Looking at the damage to the Danio I think either the other Danio or the Beta were bullying him. (Still uncertain about cause of death of the other Danio as he was "buried" before I started looking into this.
For TB or any other disease my only thought could be they caught it from the beta but when looking at the beta he is fine no issues.

 

[King Fisher]

He'll get progressively worse if it's TB. Fairly quickly. Can you or did you remove the Betta?

 

[t0ny84]

Yeah I put the beta into another tank. Will keep an eye on the Danio hopefully he can get better!
Thanks for all your help.

 

[King Fisher]

If your danio has fin damage add 1 TEAspoon of aquarium salt per 5g of water to help healing