Hydra in RCS tank

[Naughts]

I just realised the weird white palm tree things on the glass, rocks and plants are hydra. And I guess they're feeding on the shrimp larvae?
It seems that methods of eradicating the hydra will also kill the shrimp larvae and some could kill the shrimp too. Or will be ineffective (eg. Take them out manually)?
Any advise please?

 

[Back in the fold]

I had an infestation of Hydra once. No idea where they came from. And like you I had no idea what to do. There's so many so how do you eradicate them without hurting your good stuff ? I want to hear what people say on this because it can happen to anyone.

 

[Colin_T]

Hydra regularly come in on plants that come from ponds. Hornwort is a common carrier for Hydra.

You can kill hydra with copper, salt or a battery and couple of wires.

If you use copper you will have to remove the shrimp and flush the tank out well after using the copper otherwise you will kill the shrimp.

Salt can be used to kill hydra. Add 2-4 heaped tablespoons of rock salt per 20 litres (5 gallons) of water. Leave the salt in the water for 1 week and then do water changes to dilute it out.

Get a 9 volt battery (the rectangle ones) and attach a length of copper wire to each terminal. Put the other ends of the wire into the tank for about 10-15 minutes (or as long as it takes for the hydra to start dropping off the glass and plants), then remove the wire. This is normally safe for fish but I have never used it with shrimp.

 

[Naughts]

Ha ha, Colin I love the maverick battery idea but it's too scary for me!
I would struggle to remove all the shrimp to use copper as some are tiny and I have larvae less than a week old, just white specks that are similar to the closed hydra until they crawl or swim.
But salt sounds good, I guess I just need to add it slowly to acclimate them?

 

[Naughts]

I had an infestation of Hydra once. No idea where they came from. And like you I had no idea what to do. There's so many so how do you eradicate them without hurting your good stuff ? I want to hear what people say on this because it can happen to anyone.

Thanks Back in the fold.
I added a plant that I had just rinsed well. It was from a decent shop but it could have been in there i guess.

 

[Colin_T]

I guess I just need to add it slowly to acclimate them?

​

I just chuck salt in tanks but everyone here spits the dummy when I say that so yes, put the salt into a small amount of water and slowly pour it into the tank over an hour.

 

[Naughts]

I just chuck salt in tanks but everyone here spits the dummy when I say that so yes, put the salt into a small amount of water and slowly pour it into the tank over an hour.

On it, Thank you!

 

[Back in the fold]

Hornwort. That's where I got the little devils from. As for not pre-dissolving the salt, well why not ? It's going to dissolve eventually and the current will carry it. But the battery thing. That's pure genius ! Thanks Colin. I'm going to remember this well for the day they come back.

 

[nic1]

Can i also say, if you wanted to add an addition to the tank, spixi snails eat hydra! I have seen this first hand in my shrimp tank.

 

[Naughts]

Can i also say, if you wanted to add an addition to the tank, spixi snails eat hydra! I have seen this first hand in my shrimp tank.

Thanks nic1