Zebra Danios making QT tank home - now what?

So in an earlier thread of mine I evacuated my zebras from the 32g to the 10g QT that was in the middle of cycling, preparing for new fish on my list. One of the Danios is a killer and I can't tell which one so the 3 of them are in prison. However, this is supposed to be my QT tank. It's not done cycling which isn't great for them and way more work for me. Worse, either one of them is bloated or pregnant . Like..? They're pretty happy in there, no signs of stress. I'm amazed. But now what? I need that tank for new fish. Could I temporarily move the Danios back to the 32 when I bring home new fish? Then back to prison afterwards? This way they keep the tank cycled in between purchases. If I wait a couple months in between just in case there's something in that tank from the new fish? Yes I guess that means the Danios are getting moved around but I plan on doing it in 2 phases - first a school of cories, move Danios for 4 weeks - maybe not enough time for killer to get aggressive - move them back, wait 2 months then get the harlequins, repeat. OR can I get 5 cories and 8 Harlequins at the same time? That's alot in a 10g for 4 weeks is it not? But that's one back an forth move. Thoughts?

 

In my experience with danios, they are very VERY hardy and tolerate moving between tanks better than most fish. I've had to move danios several times within a few days before with no issues, so I doubt that moving them to a different tank with almost a month of rest time in between would be life threatening to them. The corries and the harlequins are too much for the 10 gallons at one time imo, and I also feel that it's easier to qt one species at a time.


I don't know which thread you're referring to where you removed them in the first place, so I'm only going off of the information I see here so sorry if I'm missing any important details! Danios aren't normally aggressive unless their school is too small, which then is when usually when they start to get too rough with other fish. You have 3 right? If it were me, I would jack up their school size and leave them in your 32 gallon that way you don't have to deal with moving them back and forth between tanks and they don't have to deal with being kept in your 10 gallon while it's being cycled. They also can be very annoying when it comes to how active they, so I totally understand if you wouldn't want to keep them in your 32 especially if the new fish you're planning on keeping are less active, like harlequins.

In short, your danios would be completely fine with being moved around a few times.

 

There is no point in flip-flopping the fish like this, you are cross-contaminating them, you might as well skip the quarantine.
I don't think you should move your fish around like that! Your aggressive danio is likely aggressive because it is stressed. There is a female pregnant with his babies, there are 4 danios that should be in a school of 9 or more, the ten-gallon tank does not accommodate the needs of such an active fish, and they are extremely unsettled in their environments that keep changing. This could lead to an outbreak of ich that will spread to both tanks.

Please use a piece of filter cartridge, and or a grocery store shrimp in a nylon stocking to hold the cycle in the ten gallon tank.

Please build up the school of danios before getting a new species of fish. It is important for all fish in the tank to keep your fish in propper sized schools so that they do not get stressed/ aggressive/ diseases.

Please consider getting more then 5 cories, they thrive in a large group. The second that one dies of old age or any other reason, you will have a group that is to small.

 

Thank-you so much for this. That's what I'll do. The history of these Danios - I've had them a couple years now. They were in a school of 7 when they were first in this tank. There's always been one aggressor - before they were 7 they were 5 but the smallest one got killed, so I added 3 more. I can't say for sure if the aggressive one is one of the originals or not, I just can't tell. Anyway, 7 went into the 32g in June of this year. I lost 2 when I accidentally got sunscreen in the tank - 2 Danios, 3 guppies, 2 platies. Lost another one and I couldn't figure it out (I now know) Added a female betta in November (my goal for this tank was to have a betta in a community tank) so was hyper focused on her behaviour and the guppies towards her. She's been great, hasn't chased or flared at any of the other fish. Doesn't shy away either. Really quite perfect. I'd noticed the Danios chasing the male guppies but didn't think anything of it. Lost my favourite male guppy - it was beat up and I was wondering if it was the Betta - then in front of my eyes watched a Danio attack my other male guppy. It was unbelievable. The Betta swam over and literally put her body in front of the guppy. My daughter and husband were watching in horror too. I asked them if I was seeing this correctly and that's what they saw. Is that possible? My daughter saw it from beginning - Danio was chasing the guppy then cornered it which is when she called me over. Anyway scooped out the guppy but he didn't make it. So, because I don't know which one is aggressive I can't trust them as a group. I think because of the history it's safe to assume it's the Danios and not the Betta who killed the other male. Needless to say I'm not getting any more zebras - these ones can live out their lives keeping my QT cycled. Also I never saw them chase a female guppy and they never got close to the Betta so I think 4 weeks should be okay.

There is no point in flip-flopping the fish like this, you are cross-contaminating them, you might as well skip the quarantine.
I don't think you should move your fish around like that! Your aggressive danio is likely aggressive because it is stressed. There is a female pregnant with his babies, there are 4 danios that should be in a school of 9 or more, the ten-gallon tank does not accommodate the needs of such an active fish, and they are extremely unsettled in their environments that keep changing. This could lead to an outbreak of ich that will spread to both tanks.

Please use a piece of filter cartridge, and or a grocery store shrimp in a nylon stocking to hold the cycle in the ten gallon tank.

Please build up the school of danios before getting a new species of fish. It is important for all fish in the tank to keep your fish in propper sized schools so that they do not get stressed/ aggressive/ diseases.

Please consider getting more then 5 cories, they thrive in a large group. The second that one dies of old age or any other reason, you will have a group that is to small.

Thank you for your reply. How many cories do you recommend?

 

Interesting story, I want to blame too many top swimming species but who knows?
how many cories for a 32-gallon? I suggest that you get a small/dwarf species like julies/false julies, panda... I would get 12, considering the amount of space in the tank. you might want 8 or 9, you sounded like you wanted a light stolking.
If you chose pygmy cories, you could get even more for the same amount of bio load. And they are super cute!

 

Interesting story, I want to blame too many top swimming species but who knows?
how many cories for a 32-gallon? I suggest that you get a small/dwarf species like julies/false julies, panda... I would get 12, considering the amount of space in the tank. you might want 8 or 9, you sounded like you wanted a light stolking.
If you chose pygmy cories, you could get even more for the same amount of bio load. And they are super cute!

Maybe error after error on my part, maybe one aggressor - who knows.

You're right, I prefer to stay on the light side of stocking. 8 or 9 it is! Thank-you for the recommendations - I'll look them up! I've seen the pandas and pygmies at my LFS and I love both of them.

 

Maybe error after error on my part, maybe one aggressor - who knows.

You're right, I prefer to stay on the light side of stocking. 8 or 9 it is! Thank-you for the recommendations - I'll look them up! I've seen the pandas and pygmies at my LFS and I love both of them.

You could also just have been struck with bad luck. I hope you do great from now on!