Nematodes and a Planarian harmful?

[katgermain]

Hello,

I bought some Asian Water Moss (Salvinia cucuilata) for cheap (it was in bad shape) at my local aquarium store. I put it in the tank and it continued not to do very well, so I've put it in its own jar, with tank water (as I've heard they get nutrients from the water), to let it toughen up a bit before putting it back into the tank.

Today i was refilling some of the water in the jar and noticed some little critters in the water. From what i can tell, the majority of them appear to be some sort of nematode? There are 4 or 5. They are 1 cm long at best and mostly just inch around on the bottom of the jar when the water is disturbed. They are very slender (barely as thick as a hair, if that) and all white from what i can see. When swimming they wiggle around either snake-like or sometimes sort of in a figure 8 pattern from what I can tell. One was creeping along the bottom and got stuck on some of the debris down there, so i wonder if it might also have some kind of texture (hairs or whatever) on its topside, but because they're so small, i can't see anything like that with the naked eye.

There's one more little guy in there, maybe 1mm or 1.5mm. Sort of tear-drop shaped with a darker tip at one end, maybe a planarian. It slinks along the bottom more like an earth worm would, sort of squishing itself up and stretching out as opposed to 'inching' like the others.

I tried to get some pics but unfortunately my camera isn't good enough to do them any justice. They just look like a little string of lint!

My tank is substrate and i vacuum and do a 30% water change once a week. The water is in good shape and i've tried to look for evidence of the critters in my tank but can't see any (though are really tough to see). I suspect they only set up shop in the stagnant, unfiltered water where the Water Moss is.

So question 1) Anyone have any further details about what these might be? They don't seem to be interested in hanging out at the top at all (i.e. so likely not mosquito larvae?).

Question 2) If there are any in my tank, of course my first concern is how likely is what i've described harmful to my fish?

Question 3) Should I just pitch the Water moss and water not take any chances? They don't seem interested in the living plants, just hiding out in the junk at the bottom. I'm reasonably sure I could just take out the moss and put it into my tank.

Thanks for any suggestions/ input!

[Silurus]

The good news is that the nematodes and planarians are free-living (i.e. non parasitic) and are unlikely to harm your fish. They are scavengers and if you deny them ample nutrition (i.e. ensure that there is no excessive food), they should not proliferate and cause a (largely cosmetic) problem.

[naturalart]

The teardrop thing with the slinky motion sounds like a leach. Some can be a parasitic and others not. I wouldn't let it get in my tank.

I agree with Silurius, the nematodes and planarian are harmless and can be managed with good maintenance.

But just for good measure, I'd quarentine those moss balls for a few weeks to starve out all those critters. there are probably more in the moss.

[katgermain]

Thanks!

The Moss is already quarantined until it gets healthy. Don't need the unhealthy bits falling off and fouling my water!

In the sunlight today I see more critters in the jar with the moss. Quite the little ecosystem in there! Should I be keeping the jar with the moss farther away from the tank? At present it's on a window sill a few feet away.

Thanks again,

Kat

[naturalart]

I dont think proximity to your tank is that important unless you see something going into metamorphosis at the surface of the water or outside your jar.