Sponge Filter

[LacertaIlla]

I'm looking to buy a sponge filter for the 55 gallon tank I have. I know my LFS stocks them, but right now the question is how to cycle it. I don't have a way (yet) to get gravel from in town back to my house (I'm a minor and can't drive a car yet, I ride my bike everywhere) and I don't like the look of bare bottom tanks, meaning I don't want to set up the 55 gallon tank until I can get gravel for it and plants.
 
Is it possible for me to put the sponge filter in my current tank and just let it sit there and do its thing for a few weeks?
 
Thanks,
Blue

 

[Byron]

A sponge filter is pretty small for a 55g tank, though it is possible, depending upon the fish.  To answer your cycling question, yes, operating a sponge filter in an existing tank of fish over several weeks will result in nitrifying bacteria colonizing it, and then when moved to the new tank it will have some bacteria, what we term seeding.
 
No mention is made of fish, so I will just say to plan what fish you intend before purchasing gravel, as some fish are better with sand.
 
Byron.

 

[LacertaIlla]

I plan on having my crayfish, Nyxie, in that tank, along with maybe some guppies or tetras, possibly snails if my 3 mystery snails breed. When I was 3 that tank used to house another Electric Blue crayfish named Sebastian, and we had him on glass beads but they got thrown out (I think a lot of them broke when we moved) and we had the most basic set up ever. Now that I've learned a bit, I want to try putting some real plants in there, as well as more "natural" hides (meaning anything that's not a glass vase so she can actually hide). The fish, I'm not too worried about. If I do decide to put some fish in there they will be on the smaller side, and I'll add them slowly so the bacteria has a chance to keep up.

 

[Chad]

Cycling is going to be the same process. You just need to make sure your sponge filter is large enough. I don't know if you can get Hydro-Sponge Pro Filters where you are but I have found them to be a good brand. Hikari has a good brand of sponge filter called Bacto that is well made as well. And if you are worried about getting enough bacterial filtration you can always run more than one. 

 

[Byron]

For a crayfish, gravel would be a good substrate, with a few river rock pebbles.  You won't be keeping substrate level fish with a crayfish.  I've never kept a crayfish but it seems likely it might eat small upper fish too?

 

[Chad]

Crayfish are fun. They were one of the first things I kept as a kid and that got me into aquatics as a hobby (tadpoles was first) and gave me a lifelong love of things with claws. 
Crayfish will be fine in gravel. If you want a more natural behavior a soft sand or silt bed with some large rocks at one end for hiding works well. Sand is easy but silt is difficult to maintain so I don't recommend it. 
 
Byron is right, crayfish will eat fish. They don't generally try to hunt them, but if the fish is sick or sleeping where it can be easily pinched it will become food. But, a lot of fish stay in the upper part of the tank, like tetra so are in no danger. I personally wouldn't keep cory or other smaller bottom dwelling fish with a crayfish.

 

[LacertaIlla]

She hides in a barrel decoration all day long, and when I've checked on her at night she is in there as well. It might be because she is due for a molt soon but I have no idea. We'll see what happens when I put her into a tank.

I ended up buying the Serenity Aquatics biochemical sponge filter (because that was the only one they had in store) and the box says it does up to 200 Litres (it was the biggest they had). The tank I have is 200L but I'm not gonna fill it right to the top, however if I find its not filtering well enough I'll go get another one (slightly smaller, so I can move it into the critter tank if a fish gets sick).

As for fish, I know not to put bottom dwellers in there. I would only put top dwellers, possibly mid dwellers depending on how I set up the tank, but no bottoms. Snails are a bit different, I know some Crayfish eat them and some don't. If she happens to chew on a few in her tank I'm not gonna be too upset, as they'll be the some of the babies from my 3 main snails in my big tank with Bruce. I'll probably have a ton more...somewhere in the tank...so it's not a big issue.