Forgotten Path

Has anyone ever considered introducing worms into a NPT in order to promote nutrient cycling? I know in terrestrial soil worms and other invertebrates aid in the decomposition of organic matter (natural mineralization) (i.e. worm poop is great for plants). Has anyone ever considered introducing worms or similar invertebrates into their NPT in order to aid in the break down of mulm/plant detritus?
I came up with this idea because I recently bought some blackworms to feed to my fish, and I understand they can survive indefinitely in an aquarium... So why not introduce some in an NPT (I'm sure they would love the soil), and let your fish control any population booms?
Is this a good idea, or is there something I'm missing that makes it a horrible idea?

WillowNatalia

Based on what I read at the link below, the worms wouldn't survive at the bottom of the tank.
http://www.skepticalaquarist.com/doc...ackworms.shtml

This link, though it looks like a commercial site, says not to have the water deeper than 1/2 inch above the worms.
http://blackworms-are-here.com/blackwormcare.html

Too bad, it sounds like a logical progression, doesn't it?

Forgotten Path

Ah, thats a great site, must have missed this article when I was reading through the material. Where does it say they won't survive?

I think the water no more than 1/2" above the worms is a precaution to ensure the worms have enough oxygen. However, I doubt they would survive in a NPT substrate. Maybe in a well matured NPT with a large aerating root system they would have a slight chance, but I doubt they would do well.

I wonder if there are any other oligochaetes that would be a candidate for the ecological position of decomposer in NPTs?

dwalstad

I think its a wothy idea.

However, the worms often don't last forever. The fish pick them off one-by-one. Also, some hobbyists complain about the turbidity the worms cause.

There are many older threads in the El Natural archives about aquatic worms. Here's one:

http://www.aquaticplantcentral.com/f...rid-worms.html

I had them in my tank and pond for awhile, but they eventually died out. One hobbyist successfully kept them in all her tanks and ponds. I don't know her secret.

Forgotten Path

Hmm. So it seems the trick would be to keep the worms in check, while still maintaining enough to make it worth introducing them...

Perhaps a solution to the "upside-down" substrate would be to use mineralized soil. There would be no organic matter in the soil layer, so the worms wouldn't eat it, and therefore move it above the gravel. They could only eat what organic matter fell into the soil cap. There might still be mounds of worm poo, but at least your substrate wouldn't get turned "upside-down". Does that sound correct?

And how would you preform good "worm management practices" to control population? Any ideas?

dwalstad

I think you just have to try it in your own setup. I don't see substrate churning as a problem. Your biggest problem will be losing the worms to the fish. Many fish will hunt the worms down until none are left. Therefore, I'd keep a portion of the worms in a separate container without fish.

Nexed

Tubifex worms might be a good idea, has anyone used tubifex worms in thier soil? Maybe they can feed your fish every now and then, you know give them something to forage after...

Forgotten Path

Tubifex worms can carry parasites that can attack your fish... Having a colony of tubifex would be like having a reservoir of of parasites somewhere where they were safe from UV/etc. At least I would be too paranoid to use them...

Maybe this is something I should try in my five gallon (the one I just setup). Unfortunately, there is no benchmark to determine if the tank does better without the worms... And I don't have the resources (i.e. $$$) or the space, or clearance from the wife to set up an identical tank (without worms). However, I could see if I could get the worms to form a replenishing population.

Now, one question remains...
How big of a population should I introduce?

Diana K

Worms count as living organisms and require oxygen and produce CO2 and other wastes.
You do not want to add so many at one time that it overwhelms the biological capacity of the tank.

Perhaps, maybe... add about twice as many as you might normally feed the fish. The fish will eat a lot of them right away, but the ones that survive (or if they die) are not so many as to overload the tank. If they all died it would be like overfeeding the fish once. And this is not a problem. If the worms lived there would be a smaller impact on the tank. Less ammonia produced than if they had died, for example. Less oxygen used by a few live worms than by the bacteria that would decompose dead worms.
If this seemed to work, no major spikes in anything you test for, then add some more worms and see what happens.

Too many = when you see worms all over the substrate. If they can get the oxygen they need under the substrate they will stay there. If it is too crowded down there they will risk coming in range of hungry fish to get the oxygen they need (or to get away from the CO2)

Forgotten Path

Hehe, I have the unfair advantage of having a tank with no fish! Once I check my water parameters, if I am clear from ammonia, etc. I will add a small pinch (maybe 10 worms). And see what happens.