ABCDemily

I have a nice, fully cycled twenty gallon. The only problem is, when I inherited the tank, it came with black gravel. It does have a nice effect on the fish, it shows up their colours.
However, it's just so depressing!
I'd like to change the substrate, however only half so I get a nice half black half beige.

Which is the safest way of doing this without harming my fish? And is it recommended at all?

Thank you!

serissime

If possible, I would put your fish in another place, whether by temporarily crowding your other tank or using a bucket or pitcher (perhaps with the heater, temperature monitored, and an airstone. Not necessary since it won't be that long). Make sure you float your filter media in your other tank. Your fish will probably bounce back just fine

ABCDemily

That's brilliant, thank you!
Also, I am planning on moving my tank, all the way across my bedroom haha, so for then they'll be in a five gallon bucket with a towel over the top.
I'd be taking half the water out, leaving most of it in the bucket with the fish. I could possibly put the substrate in then?

serissime

Sure! Better to do that kind of thing all at once I'd use that as an opportunity for a water change too.

ABCDemily

Yup! Everythings gunna be going on!

And live plants will be going in!