Salt

[Rockdog]

I apologize for my verbosity, but I'm not finding much information on The Internets about snail leeches in freshwater aquaria. This seems like a great opportunity to try to change that. captmicha and I can't be the only people to have hitchhiker snail leeches. Can we?

I have one Ramshorn snail and one snail leech in a glass jar for this first experiment. I decided to go with salt alone because I don't have a good way to regulate temperature in the little jar. I started with a dose of 3 teaspoons per gallon, as this seems to be accepted as a higher-end "tonic" dose for freshwater. The Ramshorn and the leech didn't seem to mind. So I waited an hour and then dosed them at 4 tsp/gal. The snail retreated into it's shell, and the leech seemed visibly unhappy, moving around much more than usual. After about 20 minutes the snail had come out of it's shell. Forty minutes later, I dosed them at 5 tsp/gal. Again the snail retreated into it's shell, and the leech looked even more unhappy. It seemed to want to crawl out of the water. An hour later, the snail was still deeply retreated into it's shell and the leech was still moving around near the waterline. So I upped the dose to 6 tsp/gal. The leech curled up and fell to the bottom. It was clearly distressed. It shrank to about 1/8 of it's normal size, as if it had been dessicated, but it did not immediately die. After 30 minutes the snail was still withdrawn into it's shell. Thinking that I had killed the snail but not the leech, I decided to try to save the leech for another experiment. I brought the salinity back down with a few water changes and the leech perked right up. It also turns out that I was wrong about the snail. It eventually came out of it's shell and now seems fine.
My methods were by no means properly scientific, and I only had one subject of each species, but I think I can safely conclude that six teaspoons per gallon is really hard on both Ramshorn snails and snail leeches, at least when administered in a relatively short time (hours, not days). I think a longer time and/or a slightly higher dose might be lethal to one or the other (or both).

I will allow both animals to recover for a week, then I'll probably start another experiment.

I think this time I'll increase the dose a little more rapidly to 8 or 9 teaspoons per gallon, then leave it for maybe 30 minutes. The logic behind this approach is that the snail's shell might offer some protection from the salt over short periods but not long periods, and the plants would probably fare better, too, if they weren't exposed for very long.

 

[captmicha]

Well, I may have some good news. I think I found a couple of products that might kill the leeches but leave the inverts safe. They're anti-parasites for reef aquariums. I have to call around and check on a few things first. I'll post back here with my findings.

 

[Rockdog]

I'm anxious to hear what you find out. In the meantime, I have a question.

Have you ever seen one of the leeches attacking a snail? More specifically, have you ever seen one crawl inside of the shell (or out of it)? I'm asking for two reasons. For one, if the leeches crawl inside of the shell to feed, then they may be protected from the treatment, especially if the treatment is for a short period of time. It would be even more protected if the snail has an operculum, like my Nerites do. The other reason I'm asking is because I periodically "lose" one of the leeches. It'll disappear for a few days then reappear. I've been assuming that it's feeding inside of the snail shell. Unfortunately, I haven't seen one of them for about two weeks, so I think it's gone. I don't think they'll crawl above the waterline (even when distressed by salt water), so I must have accidentally poured it out of the jar when I changed the water. But that, too, would be strange because they always seem to be attached at one end or the other. Maybe it was dead.

 

[captmicha]

Have you ever seen one of the leeches attacking a snail?

Yes.

have you ever seen one crawl inside of the shell (or out of it)?

I'm not sure. The snails are some what small, but I think that I have. After all, they have to get to the soft body of the snail to feed.

The company didn't return my email yet... So I'll give them a call tomorrow.

 

[Rockdog]

I've looked hard and long, but I've never seen leeches loose in the aquarium. I've only found four, on two different occasions, and all have been attached to plastic things that were in the aquarium and later removed. The only interaction that I've observed has been in the jar with the leech(es) and the Red Ramshorn. I've seen a leech probing the snail for several minutes, but I've never seen it go any further. The snail always eventually crawls away from it. Who knows? Maybe the leech senses the missing second leech already inside the shell?

I have Red Ramshorns, Olive Nerites, and Zebra Nerites. I know that my leeches arrived on pest snails, probably MTS, but I don't know if they feed on all common species of snails. I want to move some of the Nerites to other tanks, but I've been assuming that some of them might have leeches feeding inside of them. The Zebras are certainly big enough to hide a few leeches, and if well-fed they might be able to support one or two leeches for a long time without dying.

Please tell me what your experience has been. You're seeing them in the aquarium, right? And you have lots of them? Where do you see them when they're not attached to snails? What kind of snails do you have?

 

[Rockdog]

I finally managed to get a decent photo of my leech. It is showing the internal structure, which presumably means that it has recently fed. Most of the time the entitre leech is just translucent white.

The first photo shows the peanut butter jar and label for size comparison. In the photo the leech is in it's "normal" state, about 6 or 7 mm long. It sometimes gets shorter/fatter or longer/thinner, but this is the way it looks most of the time.

The photo even shows what I assume to be the two eyes.

 

[SMinNC]

The closest thing I had to these were some regular 'ol brown ones in my indoor pond. That I haven't seen for a while now. Had to have come in on some pond plants, then had nothing to feed on in my pond.

The second closest thing, would be hydra in my tank. So I thought I'd mention a cure for them, sense your not having much luck.

Fenbendazole

I used this stuff(the 1g pack, 3 pack) > > > http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=13555

Its a de-wormer for our 4 legged friends, from cats to horses.

Heres my thread about Hydra > > > http://www.aquariacentral.com/forums/showthread.php?t=188681&page=4

the Ramshorns seemed to do ok with it. They went down considerably in population. But I wasn't feeding them near enough food. But with that said, every Ramshorn in my house now, came from that tank.

Don't leave anything like a briggs or better in the tank with this treatment. I ended up loosing my two. Most likely(deffinately) from the treatment. Granted they were my first ever briggs. But they were growing and looking better than new, right up to the treatment.

 

[kyryah]

As far as salt, I have a decent sized colony of both MTS and ramshorns in my BW tank. (Not to mention ponds a couple of mini viviparous snails.) The salinity is achieved with marine salt and is between 1.005 and 1.008.

My mother recently used SafeGuard (Fenbendazole) to dose hydra in her CRS, RCS and Discus tanks. She did not lose a single inhabitant and all the hydra were dead in 48 hours. Here is the dosing method she used http://www.planetinverts.com/killing_planaria_and_hydra.html

As far as actually killing the leeches, I found this reference on another forum:

Some people have suggested trapping them by putting in raw meat on a string, leaving it for a few hours at night and then taking it out with the leeches attached. Don't leave the meat in too long as it will foul the water.

Not sure if it would work or not, but I guess it cannot hurt.

Kristina

 

[Tom.E]

Rockdog…FWIW, the leech in your picture is one of the Glossiphonia sp, not Helobdella. The structure of the alimentary canal gives it away. Don’t know what internet info you’re using but Glossiphonia can have 1 pair of eyes, and up to 4 pairs of eyes in some species according to Pennak’s FW invertebrate literature. Glossiphonia is probably the most common leech problem in aquariums. They’re called “snail leeches” but they really prey on all invertebrates. I’ve seen one try to pry open an ostracod. They’re also a problem in blackworm cultures.

To answer some of you other questions…

<<Have you ever seen one of the leeches attacking a snail? More specifically, have you ever seen one crawl inside of the shell (or out of it)>>

I’ve only seen this in juvenile leeches on wild caught snails. One snail I brought in had an egg cocoon hatch inside the snail shell. The inside of the shell was a moving cauldron of young leeches. Pretty bizarre to see.

<<The other reason I'm asking is because I periodically "lose" one of the leeches. It'll disappear for a few days then reappear>>

After a fluid meal both sanguivore and predatory leeches go into a hidden resting period to digest the meal. Usually in the substrate or around plant roots. So having them disappear for awhile is not uncommon. I’ve always removed the occasional leech from my fish tanks with just tweezers.

Good luck with your experiments.

Tom

 

[Rockdog]

Many thanks to all of you for the excellent information.

It's particularly good to know that snail leeches sometimes cohabitate with their hosts, even though it confirms my worst nightmare. I can remove the animals and sanitize the rest of the tank, but if the leeches can hide inside of the snail shells then I cannot be certain of eradication unless I can reliably separate the snails (Red Ramshorns and Nerites) from the leeches. I think I'll have to set up a long-term quaranteen/treatment tank for the snails, which in turn will require me to build an addition onto my house.

As for treatment, according to the thread below, Flubendazole -- the active ingredient in Flubenol -- is toxic to snails:
http://www.aquariacentral.com/forums/showthread.php?p=1195874

I'm leaning heavily in the direction of the salt treatment. My fast and crude experiment achieved a maximum salinity of 6 tsp/gal, and it caused great distress for the leech AND the ramshorn. If my math is correct, Kristina's tanks are closer to 7.5 tsp/gal. Perhaps the key is in the length of the acclimation period. There may be a "sweet spot" that the snails can tolerate but the leeches cannot. (And the Nerites and Ramshorns are likely to respond differently. Sigh. Yet another addition to the house...)

Kristina: I assume that your ramshorns and MTS came to you as freshwater animals. How long did you take to raise the salinity to the 1.005 to 1.008 range?