Changing the gravel

[Mark Hewitt]

My gravel is currently bright white with quite large sharp edges on it. I'd really like to get some Cory Catfish, but I fear they will shred themselves to bits on it! So I think I'd like to change the gravel for one which has a lot smaller and rounded edges. Also to something that isn't just bright white as albino catfish are white too, they'd disappear!

I have thought about sand but there are a few issues with sand that I'd prefer to avoid.

The question is the best way to go about changing the gravel.

I see two main ways of doing it.
a. Take my old 25 litre tank and fill it up from the main (64 litre) tank water and net the fish and put them into the tank, throw the rest of the water in the main tank away, give it a bit of a clean down and put the new gravel in, then put the fish, and the water back from the other tank. Then top it off with fresh water (probably representing about a 50% water change)

b. Take about 50% of the water out, just to lower the water level, then while leaving the fish in the tank, carefully ladel the old gravel out bit by bit and replace it with the new.

The first option has the disadvantage that you have to net the fish and put them somewhere else, which they aren't going to like at all! But has the advantage that the tank can be completely drained and the gravel replaced while it's all dry.

The second option has the advantage of not having to move the fish around, but the possible disadvantage that lots of sediment is going to be thrown up as the bottom is disturbed and we could end up with cloudy water. If that were the case would it be harmful for the fish or the filter?

 

[Blueiz]

I have done it both ways. I found it easier to take the fish out. If you take all the decorations out of the tank it is really easy to catch all the fish. You will have a stressor either way you choose to do it. IMO, the less stressful on the fish way to do it is remove them from the tank.

Be prepared for a possible mini cycle if you change it all out at one time because some of your bacteria lives in the gravel.

 

[Mark Hewitt]

Cheers, I think, of course you are right. Take all the decorations out and lower the water to 50% then they should be easy enough to scoop up. And of course put at least some of the decorations in the holding tank so they can hide in them.

I also thought that keeping some of the old gravel in the tank in a tupperware container for a week or so would help lessen the bacterial losses.

 

[BigJim]

Take the fish out. It's less stressful to move them than it is to try and replace the substrate around them.

 

[Blueiz]

You should have enough bacteria in the filter to compensate after a few days for the removal of the gravel. And you will have some bacteria on the decorations as well.. IME, it hasn't been that big of a deal, just something to watch for and if there is a parameter spike it's over within a few days, just feed a bit lighter for a few days

 

[Mark Hewitt]

You should have enough bacteria in the filter to compensate after a few days for the removal of the gravel. And you will have some bacteria on the decorations as well.. IME, it hasn't been that big of a deal, just something to watch for and if there is a parameter spike it's over within a few days, just feed a bit lighter for a few days

Good to know. My tank has only just completed its cycle so I expect there isn't massive ammounts of bacteria on the gravel anyway, mostly in the filter.

As you say, probably don't feed the day after and keep testing to make sure there are no issues and do PWC as necessary?

 

[Blueiz]

You got it

A side note, I wouldnt scrub the tank clean, i would simply remove the old gravel and put in the new gravel, maybe take a paper towel and remove some of the mulm in the tank, but thats about it. Since your tank is new you shouldn't have much of that in there anyways.

 

[Mark Hewitt]

Wonderful! btw I've found a picture of the type of gravel I have, just like this, except it's bright white. I assume this is indeed no good for catfish?

 

[eatsomepopcorn]

I would take the fish out, change it, and after the tanks clears put them back in.