Squirmy Things Came In On A Plant

Yesterday I went to an LFS looking for an edible plant for my 3-week-old goldfish fry. I was hoping for some narrow leaf anacharis. I got a bundle of that for them a couple of weeks ago, and they really really *really* liked it, so much that only a couple of tiny sprigs of it are left. But the store I usually go to didn't have any narrow leaf anacharis, or any other suitable plants that babies that tiny would be able to eat. So I went to a different store, where they sell expensive tropical fish and I've never seen anything as mundane as goldfish in there. They didn't have any narrow leaf anacharis either, but they offered a different plant (I don't remember what it's called) that they said might do. They said the plant had not been in a tank with any fish, and there was no chance of any snails or parasites or other kinds of unwanted hitchhikers on it.

So I brought the plant home and put it in my fry tank. Several hours later, when I went to feed the fish, I saw a bunch of what look like some kind of tiny larvae on the ledge of the plastic storage box I'm using as a fry tank. I didn't have my phone with my last night, so I left them where they were and got this video today:

(snapshot attached to this post). The hair the thing is climbing over is a very very fine piece of cat hair.

Besides the ones creeping up the side of the box, tonight I also saw one of them creeping along the side below the water line. All the ones I've seen, above and below the water line, were right by where the new plant is.

What are they? Are they any danger to my goldfish fry? When I take the infested plant back to the LFS and complain, is there anything I should ask for to protect the fry?

 

It might be planaria. I’m not certain.

 

I got a few of them into a baby food jar with some bits of the plant. Pictures attached, and new video at

Are these harmful to goldfish fry?

Will getting rid of the plant also get rid of the crawlies, or will there still be crawlies living in other stuff in the tank?

If getting rid of the plant won't get rid of the crawlies, what can I use to get rid of them without harming the fry?

Or do I even need to get rid of them? Are they harmful or harmless?

 

I would say that is a kind of fly larva (also known as a maggot). These usually feed on organic matter.

I do not know for sure if they will feed on fry. Perhaps if fry sit on the bottom and do not move but not fry that swim in midwater.

 

I thought maggots only ate rotting, decaying flesh? I guess plants, too?

 

I am familiar with maggots that breed in my outdoor trash can where I collect dog poop. I see them frequently when I'm tying up the bag to put out for collection. I don't think those same kinds of fly larvae live under water, do they? Mosquito larvae, yes, but flies?

If these are fly or mosquito larvae, then besides the question of whether they're harmful to my fish in the water, I have to worry about whether they're going to end up flying all over my house! :-(

 

Looks like planaria flatworms, which are generally quite harmless and tend to be featured in most tanks. Most species feed off detritus (uneaten fish food, solid fish waste), so more aggressive cleaning can reduce their population.

They said the plant had not been in a tank with any fish, and there was no chance of any snails or or other kinds of unwanted hitchhikers on it.

I'd take that claim with a large grain of salt. The only plants which I find to be rid of any hitchhikers are those grown in sterile agar cultures.

If they're receiving plants from a commercial supplier, then that's another vector for parasites, snails and other unwanted pests.

 

There are 120,000 species of fly in the world and many have aquatic larvae. Many groups have both terrestrial and aquatic species.

 

It looks a lot like a maggot to me.

 

It looks a lot like a maggot to me.

They did resemble maggots, but they had a dark center. The maggots I've seen around here are all solid white. Then again, I don't know where the plant came from.

I put the plant into a jar and am "feeding" it with daily water changes from the fry tank while I try to decide what to do with it. I think I may have glimpsed a teeny tiny snail on one of its stems the other day. Been watching for it since. Snails wouldn't be so bad. If there are snails, I'll let them grow to a size where my adult fish won't eat them, then let them live in the pond (expecting the fish will effectively control their population growth).

 

I have found something similar to this in my tank recently and I’ve actually posted here. Yesterday I think. Anyway, we’re still looking for answers as well!!!