aquariums w/o a substrate?

[Tostada]

From what I've learned here, it sounds like most of the nitrifying bacteria in a tank lives in the substrate. I guess it just lives on everything the water comes into contact with, so if you have a ton of media in your filter, there's a ton of bacteria in there. If you have a ton of plants, there's a ton of bacteria on them. But if you have a gravel substrate, the water can get around in there pretty easiliy, so I would guess that about 80% of your bacteria is in the gravel.

I guess water gets through sand almost as well -- if it's called pool filter sand, obviously it's loose enough to let water get through it pretty well and bacteria will be growing on all of it.

Anyway, I was just thinking about a Wal-Mart I was in where they had probably 30 tanks, and only a few of them had any substrate at all. We're talking totally empty tanks with a bare glass bottom and a little swirling pile of fish poo in each one.

I'm not trying to start a rant about these ridiculous superstores selling fish and not having any staff that knows anything about fish ... I'm just wondering how you can have any reasonable bio-load in there.

Say someone wanted to setup a tank with no substrate. Would everything be OK if they just got a much larger filter than they needed? I mean, if you just had a glass box full of fish, would it even be possible to stabilize it with a decent bio-load? If I was going to go without a substrate, I'd probably want the largest possible canister for a 29-gal, and I don't know what I'd do if I wanted to setup at 55 gal with no substrate.

 

[Lonewolfblue]

Well, look at it this way. Many breeders prefer bare-bottom tanks because it's much easier to clean. And most of your bacteria is going to be in the filter anyways because that's where most of the water flow is going to be. Many people use bare bottoms for their fry tanks as well, which are usually 10-20G tanks holding 50-100 fry or more. The tank adapts to it's proper condition, and if the bioload needs more, then more will build up in the filter if no gravel is in the tank. Also, a simple sponge filter run off an air pump will hold more bacteria than you think it can hold. I'm currently using them on 10G breeder tanks, and love the ease of use, and keeping the tanks clean.

 

[Devilishturtles]

Sure you can keep a barebottom tank, and lots of people do for ease of cleaning and also fry tanks, like LWB said. Adequate filtration is key, as well as water flow.

 

[Fishyfanatic]

I just want to echo Lone and DT. The bulk of the beneficial bacteria is in the filtration, not the substrate. Barebottom tanks are common among Discus keepers also.

 

[7Enigma]

And these super-mega LFS' generally have large filtration systems in back rooms that would shock you. Basically large sumps that have a tremendous biological and mechanical filtering capacity. That's why its so important to check adjacent tanks to the tank you want to purchase a fish in. If you see dead fish or infection/parasite/wounds, its very likely the fish you are looking at has been compromised as well.

 

[sabbott1877]

Also, Doesn't a lot of the stuff that the bacteria breaks down "Hide" in the substrate, and therefore, if you clean it off of the glass bottom frequently it doesnt need to be broken down...?

 

[7Enigma]

Well the "stuff" is uneaten fish food, fish waste, and plant debris that if left to rot will produce ammonia. If this never rots into ammonia, then yes you have a lower bioload in the tank and water changes would not need to be done as frequently (if no plants or algae are present).

 

[sabbott1877]

Ya what he said... I guess i could have worded my post much better...

 

[DepotFish]

I have barebottom tanks. Most goldfish enthusiasts I know have barebottoms. Most bacteria is in the filters.

 

[Lonewolfblue]

And like stated above, if you have decent filtration, and good "circulation", there's no need for gravel. And sponges hold a tremendous amount of bacteria.

 

[hc8719]

alot of fish feel safe with substrate, especially bottom dwellers, like kuhlis, cichlids and goldies love to uproot plants and pebbles as well. personally i think they look better, and the fish enjoy them.

wal-mart and other stores dont use substrate to keep the tanks cleaner, and prevent a big spikes in params

 

[severum mama]

You know, I was researching discus and I came across an interesting take on a bare bottom tank for those who don't want to look at just plain glass, but want the ease of cleaning that comes with a bare bottom. You can just paint the bottom of the tank. I think the person that was talking about it on the discus forum used the same kind of paint on the bottom of the tank that Lonewolfblue used on his planted tank... the speckled looking spray paint. It gave the tank more of a "gravel" effect than just plain paint would. It's kind of a cool idea, but I prefer to have a substrate personally. If you want a bare bottom tank it might be something to think about.

 

[rkilling1]

well, I am going to have to argue that most of the bacteria is NOT in the filter, but in the tank itself. In a well established tank most of the bacteria is on the walls of the tank, substrate and decor.

 

[Guest]

well, I am going to have to argue that most of the bacteria is NOT in the filter, but in the tank itself. In a well established tank most of the bacteria is on the walls of the tank, substrate and decor.

I am sorry, however this is not correct. In a freshwater tank, "most" of the bacteria is established in the filter media. Bacteria will also establish on other surfaces, however the majority is in the media. That is why you should never change it all at once, and keep it wet while performing cleaning, ,moving etc.

As stated, sponges, as well as bio-media/wheels...grow a lot of bacteria.

 

[joannde]

Hi - I too have a barebottom tank. I never have to worry about excess mulm - and the tank is planted too ! I have five pots (with EcoComplete) for 3 swords, a bunch of wisteria and one with a mix of L Repens and Sunset Hygro. I have tons of anubias and java ferns attached to ceramic pieces I've made (rocks, driftwood, etc would work also).

I have to admit, I hardly notice that the tank doesn't have a substrate and nobody who's seen it has ever commented either. So ... it IS possible to have a bottomless tank that doesn't look like a temporary setup.

And I have no problem with maintaining enough bacteria. Even before it was planted it was never an issue. Those little guys will attach themselves to anything LOL

Photo of my tank:
http://www.aquariumadvice.com/photopost/showphoto.php?photo=12236&cat=500&ppuser=13767

Unless and until I set up a tank for cichlids I'm probably going to continue to go barebottom. I enjoy watching the inhabitants from below as well as from the side LOL