Casualty - Should I Replace Him?

[Rynofasho]

So we have a Danio that was tormented and beat up and ended up having his tail split. He lived for awhile but was clearly doing poorly so we put him in a separate tank to go. I looked at fin rot pics and all that and I am sure it is not fin rot -- he just got beat up on and couldn't tough it out. Sad -- our first fish loss

My question is should we put just 1 fish in the tank to replace him? We have a 36 gallon tank that is cycling currently (checked water parameters, they are ok and other fish are thriving) and we now have 5 danios as opposed to 6. I wanted to try to keep them in a group of 6 but I don't know if it is bad to stick one new fish in with 5 others that have established spots in there. Is it ok to do? If it is alright and they show some aggression should I just move everything around in the tank so they have to claim new spots? Please let me know. Thank you.

 

[Jenste]

if you are currently cycling, then NO do not add another fish - chances are that it may not be able to handle the stress of an improper environment and also die.


just stick with the fish you already have in there and please hold off until you have sorted out your cycling.


his shredded fins could have been from poor water quality - if he was already stressed then his immune system would not have been able to cope with an uncycled tank and constant exposure and ammonia burns.

build up the school once the tank is cycled and not before...then you will be fine. danios are not territorial.

 

[Biulu]

What kind of danio do you have? Some people recommend to have uneven numbers with more agressive shoaling fish, but I don't know what the reason for this is. You can add other danios, but try to ensure they are the same size or larger. Normally a smaller fish gets picked at.

 

[Rynofasho]

I'm not sure how a shredded fin denotes poor water quality. I do 25% changes daily and have a very small bioload in there currently considering the tank size. I also watched him get picked on pretty routinely by the bigger danio.

I'll go ahead and hold out for now though like was said. At least then I can see if any other fish start to look in poor health. This guy didn't look very great from the get go --- I should have opted for a different fish from the pet shop. I suppose I know now for next time though.

To answer the other question, we have long finned zebra danios. There is really only one fish that is really aggressive - he pretty much patrols the top of the tank and chases everyone off who comes up there, especially with the tank light on.