Leeches

[Moulderman]

I was given a 40 gallon aquarium with 100’s of cherry shrimp, 10-15 rabbit snails, 20-30 rams horn snails, 2 bristle nose plecos, and 2 dwarf blue crayfish.  To my horror, I have discovered that there are leeches in there too!  What can I use to kill them or should I just accept them as part of the ecosystem?

[Fishmonger_X]

How big are they? I have leeches in some of my tanks. They don't attach to my fish and suck their blood or anything. They might be harmless.

[Daniel]

I get leeches like this all the time and I feed them to my discus.

 

[Aubrey]

I too have recently discovered leeches in one of my tanks. I'm not an expert on them, but after some research and observations, I believe the ones I have are harmless to fish. They do, however, seem to eat snails. I say "seem to" because I have never witnessed them on a snail, but the internet says they eat them and I have noticed a significant decline in the Malaysian trumpet snail population. Although that might be skewed because I also have assassin snails in that tank but have not noticed any empty assassin shells. The sight of the leeches makes my skin crawl, but I suppose if they are doing a better job at keeping the Malaysian trumpet snail population in check than the assassins and not harming my fish then they can stay.

[Brandy]

The only leech I have ever seen in real life was on my knee. Oddly that did not bother me at all (I laughed very hard at all the high school boys screaming girly screams and running from the water🤣), but the idea of them in my fish tank seriously disturbs me. 😨

[shkote]

It really just depends on the type of leech. Snail leeches are predatory towards snails and spend most of their time hiding in the substrate. It's pretty common for Rabbit snails (mostly wild collected) to carry leeches. Unfortunately pretty much anything that will kill leeches will also kill your shrimp and snails.  But let's focus on the fact that someone gave you a 40 gallon full of awesome inverts and BN plecos 👍😊 That's a win!

[Another Jake]

Nice timing. I just found this in my tank today:

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Only one thing to do I guess.

[Another Jake]

... But seriously, what do you do? Can they be trapped?

[WillMcK]

On 11/24/2020 at 6:47 PM, Another Jake said:

Nice timing. I just found this in my tank today:

 

 

I recently found those in my tank too...I have neon tetras and CRS. I've pulled out the ones I can with tweezers when I seem them but I know there's more hiding, and probably eggs too.

 

Are they dangerous? Should I care or just let them be? They are nasty looking...

[Another Jake]

No, they seem harmless to me. Haven't ever seen them attacking fish/snails/shrimp. They just hang out in the substrate and occasionally pop out for a swim. Creepy? Yes. Dangerous? No.

I occasionally put a trap in the tank if I get tired of seeing them in the substrate. You can use those glass planaria traps if you don't mind catching some tiny snails too. I doubt that you'd end the infestation, but you can decrease the numbers if you want.