Worried New Aquascape Will Kill Fish

[David J]

Hi

My tank has been fully cycled for just over a year. I am currently planning a complete overhaul. I haven't completely settled on the style yet but it will involve a complete emptying of the tank including the current substrate which I will be replacing with a more specialist substrate for plants. I'm intending on starting with co2 and replacing the current wood and rocks and all new plants. New lighting and even a new background. Everything is changing except the tank, filter and fish.

Although I will be using the existing cycled filter, I am concerned that by removing the substrate and hardscape I will affect the size of the beneficial bacteria to the point fish will suffer.

I know a substantial amount of bacteria live on these. Will the amount in the filter be enough? Any tips from anyone? I am in no hurry to do this. I'm currently buying up everything I need gradually so probably a couple of months away from doing anything.

Thanks

David

 

[fluttermoth]

You will lose some bacteria, yes, but with a bit of thought, you shouldn't lose any fish.
 
Fast the tank for at least two days beforehand, so the fish's wastes are reduced to a minimum, and feed sparingly for a few days afterwards as well.
 
Test for ammonia and nitrite daily for the first week or so, as you might need to do a few extra water changes while the bacterial colonies recover.

 

[David J]

Thanks for the reply. Good thinking about the feeding. Wouldn't have thought of that. I've also heard that some of the specialist substrates need cycling for 3 weeks before fish can be added. I don't see anything about that in the ones I've looked at so far. Is it a certain type that need this I wonder? This would be a problem as the tank I'll be putting the stock into is small and I wouldn't really want them in there more than a day.

 

[fluttermoth]

I've never used anything like that, so I'm not sure!

 

[David J]

Ok. Anyone else any idea?

 

[looking-glass]

Ive not heard that they need cycling i know with a lot of them they just recommend you wait a while as they take a bit of time to clear  

 

[David J]

Cool. I think it was a video on the green machines youtube channel that mentioned it.

 

[Gruntle]

Is your current substrate gravel? Would you have room in your new tank to put some of it in a mesh bag for a while, and gradually (a handful at a time) remove it?
 
If I remember correctly, it's the top inch or so of your substrate that holds the most bacteria, so if you were to harvest that you'd be doing the most good for your fish.
 
I would have thought that way that the bacteria would continue to work, and as you remove it slowly, the other bacteria in your setup would find places in your new setup to colonise. It might help, but I've never had the need to try so I could be talking rubbish.

 

[simplyfish]

You could also put any items from the new hardscape into the current tank for a while, they may pick some colonisation up. I wouldn't expect a lot from this, but marginal gains can help... 

 

[mhancock]

I've re-scaped completely and only kept the bacteria in the filter (extenal) which has been fine, the idea about feeding and monitoring from fluttermoth seems good!  Are you going to put some before and after pics on here?