Beneficial leeches?

[octanejunkie]

While swapping substrate on our 6G Cyl Tank this weekend I found two of these while sifting and rinsing the old gravel

I'm pretty sure these are leeches, only 2 found and both this size. They attach to things from one end only, swim like snakes *undulating) and can expand and contract. The tank has only smaller fish, so I doubt these could attach to a fish without us noticing rather quickly.

The question is: if these are harmless detritus leeches, are they beneficial to our tank's ecosystem and should we keep them or toss them out?

And, how can we positively ID them?

Thanks in advance

 

[aluka]

i would just dangle them over a fish and let them have it as lunch. Critters are not someting that aquariums lack when they are doing well. Better get rid of it when you can then try to find it when you cant

 

[octanejunkie]

Better to get rid of it when you can, than try to find it when you can't

I like that

 

[Fishfur]

I'd agree. I had FW leeches once. I could not get rid of them no matter what I did, including breaking the tank down to bare glass and sanitizing everything three times. I tossed the substrate finally, seems their eggs can survive almost anything.
You'll end up with hundreds of them if left to their own devises.

 

[octanejunkie]

I'd agree. I had FW leeches once. I could not get rid of them no matter what I did, including breaking the tank down to bare glass and sanitizing everything three times. I tossed the substrate finally, seems their eggs can survive almost anything.
You'll end up with hundreds of them if left to their own devises.

Yea, I pitched them when I pulled the substrate... I hope not to find them in our newly rescaped tank anytime in the future!

 

[Fishfur]

Wish you luck with that.

 

[octanejunkie]

Wish you luck with that.

Um, thanks... don't sound so reassuring

 

[Wy Renegade]

Why is it that freshwater people are so opposed to using biological methods for breakdown of wastes? In a saltwater tank we add all kinds of things to try and improve breakdown and filtration, in freshwater everyone is like OMG sterilize it! If in fact they are detrivourous leeches (which btw the vast majority of leeches are), then they can only benefit the tank by being there - they will help to breakdown left over food etc. in the tank after you feed.

No personal judgment by the way, I just think that the philosophical differences between the two types of tanks are humerous.

 

[aluka]

Why is it that freshwater people are so opposed to using biological methods for breakdown of wastes? In a saltwater tank we add all kinds of things to try and improve breakdown and filtration, in freshwater everyone is like OMG sterilize it! If in fact they are detrivourous leeches (which btw the vast majority of leeches are), then they can only benefit the tank by being there - they will help to breakdown left over food etc. in the tank after you feed.

No personal judgment by the way, I just think that the philosophical differences between the two types of tanks are humerous.

I have never had a saltwater tank, but in freshwater, there are lots of critters that are harmful to our livestock. I breed shrimps, many critters besides the basic nemotodes, limpets, etc can wipe out my whole colony. So alot of times its better safe than sorry.

I think you can think of it as if you found a hitchhiker that looks like a mantis shrimp and you can't tell if it is one or not, and that thing will likely crack your tank and cause a leak if it is.
I would get rid of it just in case, lol

 

[octanejunkie]

Why is it that freshwater people are so opposed to using biological methods for breakdown of wastes? In a saltwater tank we add all kinds of things to try and improve breakdown and filtration, in freshwater everyone is like OMG sterilize it! If in fact they are detrivourous leeches (which btw the vast majority of leeches are), then they can only benefit the tank by being there - they will help to breakdown left over food etc. in the tank after you feed.

No personal judgment by the way, I just think that the philosophical differences between the two types of tanks are humerous.

Yea, Wy R, you are right, in a way. Everything in nature has it's place, and a reason for being there. I had heard and read so many "horror" stories about unexpected/unwanted inhabitants that I just erred on the side of caution and flushed them.

Without finding the reference again, wikipedia I believe, there are around 700 species of leeches; 100 marine, 90 terrestrial and the rest freshwater. Of all of those 90% are nematodes and feed on decomposing flesh, open wounds, etc - basically they are opportunists, but this does not make them harmless.

Leeches themselves may be harmless (feed until full and fall off the host) but they can introduce other unwanted visitors. Leeches carry viruses, bacteria and parasites in their digestive tracts. Not knowing their origin or gutload, I would be reticent to allow any unknown host or pathogen into my "controlled environment" - and that is exactly what a fish tank is.

In our arrogance to control and contain nature, we omit, overlook or simply are ignorant to the entire ecosystem. Our actions, or inaction, can easily miss the gentle balance nature accounts for, which can turn a happy fish tank into a cesspool in relatively short order.

If we can identify and quantify a species to determine it's benefit, yes, live and let live - which is why so many of us have a QT tank. If we cannot, should we risk the entire community while "playing god" with our little ecosystems?

Sorry to get all religio-politico-scientifico up in here, but if I can't ID something as a "beneficial species" to my tank and it's inhabitants, I don't want to chance adding it, or, if I didn't know it was there, leave it in there, once I find it.

But hey, I'm a control freak

 

[Wy Renegade]

Yea, Wy R, you are right, in a way. Everything in nature has it's place, and a reason for being there. I had heard and read so many "horror" stories about unexpected/unwanted inhabitants that I just erred on the side of caution and flushed them.

Without finding the reference again, wikipedia I believe, there are around 700 species of leeches; 100 marine, 90 terrestrial and the rest freshwater. Of all of those 90% are nematodes and feed on decomposing flesh, open wounds, etc - basically they are opportunists, but this does not make them harmless.

Sorry to get all religio-politico-scientifico up in here, but if I can't ID something as a "beneficial species" to my tank and it's inhabitants, I don't want to chance adding it, or, if I didn't know it was there, leave it in there, once I find it.

But hey, I'm a control freak

That was pretty good from memory, but the word you are looking for there is hematophagous rather than nematodes, meaning they feed on blood. Nematodes are roundworms rather than segmented worm (annelides) and all leeches are annelides.

No problem on the "religio-politico-scientifico" side, like I said, I just find the difference in attitude humerous. I also understand trying to maintain our little glass box as cleanly and beneficially as possible.

 

[jlk]

I will just add my two cents on the leech situation. Seeing these vile things on my fish, having to gut my one tank entirely multiple times as these things are literally indestructible and eventually having to euthanize an expensive fish as the result of infection from leeches, I don't wish these things on my worst aquatic foe. Perhaps they are not all 'bad' but my skin still crawls at the thought of these things. End of story.

 

[octanejunkie]

I will just add my two cents on the leech situation. Seeing these vile things on my fish, having to gut my one tank entirely multiple times as these things are literally indestructible and eventually having to euthanize an expensive fish as the result of infection from leeches, I don't wish these things on my worst aquatic foe. Perhaps they are not all 'bad' but my skin still crawls at the thought of these things. End of story.

Horror story #378...

Sorry for your trouble and your loss