Effective against hydra?

This problem is hard to avoid from time to time if you use natural plancton. Some fish are able to eat them if they have nothing else to ffed on. Did you try that? If you have no experience with using some kind chemicals with Paros I would use the good old way that is very efective and safe. If you have any kind of hydra that does not have symbiotic algae to help them survive (is not green) you can try to starve them to death first. . Just use for example black (Culex mostly), white (Chaoborus) or other kind of mosquito larvae. Something big that they will most likely not catch becouse it will not spread over the tank before its consumed by fish. It sometimes works well if your fish are eager enough eaters, unless you have alot of infusoria or rotifera living in your tanks. Limitation of light would be necessary with the green ones. In such case remove the fish as no light for several days would not be good for them , natural fotoperiod is very important. If you are unsuccesful starving them this way, use a little piece of soft copper (some kind of wire or so) and just hang it in the water of the tank. Hydras tentacles will start to shorten and as they loose them you can already remove the copper. Hydra will die of starvation.In the very soft and acidic water this could take hours and the copper disolved in the tank water will bond to organic matter like detritus, peat, leaves and stuff. It works well enough to kill the hydra before the level of disolved copper starts to be dangerous for fish. If you want to be realy safe, just remove the fish for the treatment. How quickly it works is dependent on ammount of organic material in the tank for the copper ions to bond. If you clear the tank it will work faster but of course the level of toxic copper ions will be higher.Do not use it with eggs in the tank. This way you dont have to risk contamination of the tank environment with potentialy harmful substances. I hope that helps. + If you want to prevent the hydra from getting in to your tanks, next time you bring the plancton home, leave it in some bucket for like an hour and than pour it somewhere else. The hydra will attach to the first bucket and you dont have to solve this problem that often.

In France we use Dolthene against Hydra. It’s a vermifuge for dogs available on pharmacy and it works good.
No problem with the fishes.

Well I was not speaking negatively about all chemicals and of course using for example copper sulfate and dosing it in to the tank is very dangerous. The method with soft piece of copper metal was suggested by RNDr. Stanislav Frank in his books where he describes this way as quite safe as you dont get high concetration quickly and if you watch it closely you can use it quite safely as the concentration that becomes highly toxic for hydra are usually not dangerous for the fish yet. I think we can agree that most of the substances we use to get rid of parasites or pests are usually just less harmful for fish than for these organisms. If flubenol is safe for use with Paros, its great. I have used above stated method many times even with some quite sensitive SA imports. But you are right Peter, there may be methods that are safer for use for people who are newer to the hobby.

Hello!
I don’t understand that panic about those unplanned guests (o.k. I wasn’t pleased about my little dragonflies in my new tank, but I’ve got them out just by searching them out in a nearly emptied tank)’.
Once I’ve also had hydra in another tank, we tried to get them out with wooden sticks. But they vanished before I could bring some to a teacher of biology who wished to get them.

Also we got planaria as unwished guests, I catch them out with a meat trap.
I would never risk some chemical substances in the tank.

I would rather make a new tank for the fish and shrimp than to use any poison!

I guess we have much more unknown guests in our tanks than we want to know.
And nevertheless, it’s always a way of biological balance …

OK
I do not often Hydra, but as I’m starting to 95% of my food in the great outdoors and’ll feed my fish does that happen now and then. I have never lost a fish by Flubenol. However, all die snails, planaria and other molluscs. Since I have no shrimp I can not tell you how they react to it.

How does it look with your Hydra, could you be helped

It just goes with Flubenol. If you no longer feed them it will be less but they remain. Also a new aquarium will not help, somewhere is always a left and multiplies.