Hydra Outbreak

[GaryE]

I am a friend to all Hydra, in the way some people have freeloader 'friends' who show up and never go away. I have always gotten them from plants. It can be questionable, because without the right conditions, they can sit quietly in hard to notice corners for a long time. Then, along comes food and boom, they're quicker than bad luck.

You can add plants and not see them for a few months.

They're wonderfully variable. I actually have 2 species here, the stubby green ones and slightly larger pinkish white ones with longer stingers on them. Fish avoid them, with the exception of rainbows, which are among the stupidest vertebrates I've ever seen. I've seen 1 cm bows with lacework stinger scars on their backs swim right into them over and over while I was trying to get a clear run at the Hydra with peroxide.

 

[Naughts]

Hey @Back in the fold , how do you feel about salt treatment? That got rid of hydra in my shrimp tank...

Hydra in RCS tank

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? :blink: 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...

www.fishforums.net

 

[Sir Guppy]

I found a video that could be helpful:

You’ll want to skip to 9:15 though.

 

[Back in the fold]

@Naughts I’ll give that a try . Salt does wonders for lots of things and is simple and cheap . Thank you for this advice . How did you remember that old thread ? I just now read through it and all the answers are there . @Colin_T and his battery trick is certainly intriguing .

 

[Back in the fold]

I made up change water with four tablespoons of aquarium salt in five gallons of water and went to work . One hour after the water change the Hydra look sick and appear to be dying . They are no longer waving their tentacles in the current and fishing for a meal . They have shrunk back and I even saw some falling dead from the floating Hornwort . I’ll watch this closely and begin a change to fresh salt free water Sunday if it looks like the Hydra are completely dead .

 

[Back in the fold]

Twenty four hours after the heavy salt treatment and the Hydra are diminishing rapidly . I fed BBS this morning and very few Hydra made any attempt at feeding . This picture shows the heaviest concentration of them . This is way down . This is a bare aquarium , no substrate and the bottom is littered with Hydra carcasses . I’ll let this sit one more night to be sure they’re on the ropes and then start diluting this salt out tomorrow with a good water change .

 

[MaloK]

In Diablo, Hydras resist many attacks. I got to add salt to my weapons.

 

[Innesfan]

Salt does wonders for lots of things and is simple and cheap .

As Innes said in 1935: "Salt is Nature's remedy for many ills. It is effective in most troubles of freshwater fishes." Add hydra-eradication to the list.

 

[Naughts]

Twenty four hours after the heavy salt treatment and the Hydra are diminishing rapidly . I fed BBS this morning and very few Hydra made any attempt at feeding . This picture shows the heaviest concentration of them . This is way down . This is a bare aquarium , no substrate and the bottom is littered with Hydra carcasses . I’ll let this sit one more night to be sure they’re on the ropes and then start diluting this salt out tomorrow with a good water change . View attachment 360043

Wow, there were a lot!

 

[gwand]

Twenty four hours after the heavy salt treatment and the Hydra are diminishing rapidly . I fed BBS this morning and very few Hydra made any attempt at feeding . This picture shows the heaviest concentration of them . This is way down . This is a bare aquarium , no substrate and the bottom is littered with Hydra carcasses . I’ll let this sit one more night to be sure they’re on the ropes and then start diluting this salt out tomorrow with a good water change . View attachment 360043

What was the final concentration of salt in your tank. Thanks.

 

[GaryE]

Salt didn't work here. It messed them up, and I thought I'd gotten them. But before long (a couple of different tanks at different times) it was back, waving at me.
If i weren't worried about the other life in the tank, I'd permanganate the plants (a trick I learned reading Mr Innes), heavily salt the filter and flush the tank with as hot water as thought safe for the glass. Or warm salted water.

The amount/percentage of salt I needed for killing it off was enough to kill everything off.

 

[Innesfan]

I'd permanganate the plants (a trick I learned reading Mr Innes)

It won't surprise you that that's what I do.

 

[Back in the fold]

What was the final concentration of salt in your tank. Thanks.

4 tablespoons to five gallons . That’s a lot of salt . I noticed my Ramshorn snails were looking a little sick too . Gary is right , that amount of salt will kill other things too . I diluted it out today and things look good .

 

[Rusty_Shackleford]

Hmmm . . . . I don’t “think” so but I really don’t know for sure . In the past on this forum several people have asked whether they should quarantine new plants and the advice was usually no but I now think differently .

Quarantine is good. Quarantine combined with reverse respiration is even better and will prevent any similar situations in the future.

 

[Back in the fold]

Final update on the Hydra and their close encounter with a heavy dose of salt . It worked . They are dead , dead , dead . Lots of dead ones floating lifelessly throughout the water column . Besides that , the fish , snails and plants look okay . Still diluting out the salt with every other day 75% water changes .