We have Hydra in my Cory fry tank.

[hoplo]

Hi all,

We have Hydra in one of our Cory fry tanks.

Will it be hurting the Cory's in anyway?
How do we get rid of it?

Vicky. xx

[andywoolloo]

Sorry I cannot help you but wow, I had to look that up. I read they are like mini jellyfish and they sting and can kill teeny fry. I am peering into my tanks now, searching. The article I read said heating the tank very high kills them but you'd have to remove the fish for that! Spooky!

I found some links here at planetcatfish on hydra the last one is really interesting!

http://www.planetcatfish.com/forum/view ... =6&t=18242

http://www.planetcatfish.com/forum/view ... =6&t=15937

http://www.planetcatfish.com/forum/view ... =4&t=17598

[Richard B]

A quick surf of the net has provided many suggestions - i can't speak from personal experience however.

Heat, salt, Panacur (de-wormer), hydrogen peroxide, copper sulfate, Gouramis (pearl & 3 spot)are all mentioned but i suspect the fry might well suffer as well.

I'd wait for someone's post with actual experience.

[Mike_Noren]

I doubt hydra eat fry. I had hydra covering every surface of a fry tank like a "fur", but they didn't even seem capable of eating tiny cyprinid fry. However, they will compete with the fry for food, so I suppose it might be worth getting rid of them.

I eliminated mine by adding salt up to 3 parts per thousand (by weight, ie 3 grams salt per liter/kilo water), which led to the hydras disappearing within a couple of weeks. This is harmless to fish (at least short-term), but will kill most plants.

Hydras are sensitive to copper, but what isn't; it's nasty stuff. If I had hydras and wanted to get rid of them, I'd probably use 25 ppt formalin, or, failing that, I'd dose antihelminths such as fenbendazol/flubendazol. This also kills snails, but not shrimp, and wont mess up your filters too much.

Basically anything which kills ciliated organisms like ciliates, flatworms and snails is likely to also kill hydras, so one strategy could be to look for Ich medications which are marked as not safe with snails, it'll likely kill hydras too.

Peroxide and permanganate no doubt also works, but I have limited experience using those as medications.

I have zero confidence in biological control using gouramies; maybe they'll eat them if really starving, but mine much preferred fish food.

[hoplo]

Thank you for the info guys, i will let my hubby know.

Vicky. xx

[mummymonkey]

Hydra certainly kill cory fry if there are enough of them.
I used Flubenol to kill hydra and it was very effective.

[apistomaster]

Hydra can definitely bring down Corydoras fry.
I had my first serious Hydra problem in my fish keeping/breeding career only in my latest fish room iteration over a period of 40 years and I was able to eradicate them from all my tanks by using flubendazole 10% powder. It only takes approximately 1/2 teaspoon/20 gals to wipe them out. The effective dosage is very wide ranged so exact amount used isn't very important. Treat all your tanks at the same time for about 10 days or re-infestation is almost certain. It only takes a piece of one and a little luck to get them re-established. Flubendazole is so much safer to fish and plants than any of the older recommended methods of control. I tried everything without any effect until I used flubendazole.
Some shrimp spp are pretty sensitive to flubendazole so be careful if you use it with them. I'd keep a back-up shrimp culture going just in case. Very high doses may kill snails.

[cmstwc]

woooo,very interesting. I never know there is such creature exist!

[Mike_Noren]

Some shrimp spp are pretty sensitive to flubendazole so be careful if you use it with them. --- Very high doses may kill snails.

My experience is that pretty much any dose will kill snails, but that even 5 time recommended dose did no apparent harm to either amanos or cherry shrimp. What species are sensitive?

[apistomaster]

Hi Mike,
My experience was different from yours.
Snails seem much more tolerant to flubendazole than shrimp. I can't say any of mine died but some people have told me they have lost some of their snails. I tried to use it to kill MTS and Pond snails but that did not work.
The shrimp that suffered for me were "bumble bee' shrimp. They are least hardy of the shrimp I have kept. It is entirely possible that they died out for other reasons and the loss was coincidental to the treatment.
There also seemed to me to be a loss of the smallest cherry shrimp in one small tank which received a fairly high dose compared to what I used in other tanks. These were the only shrimp species I had at the time.

[Mike_Noren]

Snails seem much more tolerant to flubendazole than shrimp.

I had a suspected outbreak of parasitic protozoa in an aquarium, and decided to use fenbendazol, a substance related to flubendazol, so I expected them to behave similarly.

Recommended dosage is allegedly 2 mg/liter.
I was worried about mortality among my shrimp and snails, and decided to set up a test. So I put a selection of expendable snails and shrimp in a 10 liter container.

I added 1.25 grams fenbendazol (five pulverized Axilur-for-cats tablets), about 60 times the recommended dose, which killed most snails (MTS, Physa, and neritids) within a few hours. The neritids were the most sensitive. After 72 hours cherry shrimp and amano shrimp were still healthy, but only a few MTS showed any signs of life and all died shortly after. After returning the shrimp to the main tank I kept tabs on the amanos, and they lived for at least a few months after this.

I then treated the main tank (after having removed my most prized snails). 2 mg/L would equal 1/4 tablet which was impractical, and I already knew fenbendazol was effectively non-toxic to fish and shrimp, so I opted for double dose. This eliminated all non-MTS snails and the majority, possibly all, MTS within two weeks, but didn't kill a single shrimp or fish.

I haven't tried with bumblebees, and I suppose it is possible that they're far more sensitive than cherry shrimp, but I would suspect your losses were unrelated to the medication.