Watashiwasakana

i have this long established fish tank, my 20 G long, and i will be moving my fish to my larger 55 G, which will leave my tank empty. There is a well established sponge filter driven by a powerhead in it. If i changed the substrate to sand, would I lose my cycle? I also want to know if i can make a tank only for cherry shrimp.

Amanda

If you remove all of your substrate at once, yes, you will be thrown into a mini-cycle.

Watashiwasakana

oh, i have gravel right now, but i want to use sand, is there any way to do that?

Watashiwasakana

oh, i forgot to mention, it has quite a lot of plants in it, so could i do a silent cycle?

Shaina

If you are heavily planted you may well do a silent cycle.

To be safe, however, you could replace all the substrate and leave a netting bag of the old gravel (don't let it dry out) in the tank for a week or two to give the new substrate time to develop enough of a bacteria colony to offset the gravel removal.

If you are removing the fish as well and just going to have the shrimp in there, though, I wouldn't worry about it. The bacteria in your filter and on your plants, in addition to the consumption of your plants and the much lower bioload of the shrimp should prevent any issues. That's just IMO.

Watashiwasakana

yeah, im moving the fish

Ricardo_NY1

What is really likely to happen is there will be no mini cycle because unless you're going to throw 400 shrimp into the 20 gallon, the bio load will be extremely low. The sponge filter might already have more bacteria working than you'll actually need or can support with just shrimp.

I don't see a mini cycle........if anything, your tank will end up losing whatever bacteria is left after the gravel is out because there will not be enough of a load to feed it.

As an example.........you can take a 5 gallon tank......throw 20 shrimp in it and place a sponge filter with some media added from an established filter........and you will not lose any of your shrimp.........not something I'd recommend for others.......but that is exactly what I did with the two 5 gallon shrimp tanks I am running right now. I did check parameters here and there just incase, but no action was ever necessary.

You can definitely have a 20 gallon as a shrimp only tank.........and at the rate the CRS breed, you'll see over a hundred in there in no time.