5 gallon riparium update - day 6: I got hydras 😞

[Thermal]

Recently found hydras hanging out in my 5 gal and since the tank is only 6 days old, I'm assuming it's normal to have small infestations like this?

My concern is, should I just let them do their thing? I know they're a threat to baby shrimp, and baby fish, but I don't have any of those and I'm not planning on getting any, so that makes them pretty much harmless?

I heard that snails would gobble them up too, I have bladders and rams but they don't really give a damn, especially that guy in the back.

Holding back on using any medicine right now as I don't want to accidentally harm anything else in the tank, but I have hydrogen peroxide at the ready just in case they get out of hand. I probably wouldn't even try to remove them if they do happen to not be a threat, also I wanna see what they do..

going to be adding a betta in 2 months and nothing else. I doubt the hydras will be a threat to it, though I'm concerned that they will multiply. Will they just go away on their own once the tank gets older? Like how new tanks always get microfauna population explosions, that go away after a few weeks?

 

[Colin_T]

You can kill them with copper or salt (2 heaped tablespoons of salt per 20 litres of water).

If you aren't planning on breeding fish they won't be an issue and you can leave them be. They will grow if there is food for them. They will eat newly hatched brineshrimp, baby daphnia, copepods, single celled algae, and anything small enough. If they don't get any food they won't breed and you won't have many to worry about. If they get food, they will breed at a rapid rate.

They don't normally occur in aquariums and come in on plants. Snails don't touch them and neither do fish.

 

[GaryE]

They will always be there now, but food sources should limit their populations. If I have fry and feed freshly hatched artemia, the hydra multiply rapidly. When the fry move out and the feeding changes, they vanish, to the eye. I know they're present feeding on the micro-organism life of the tank, but they stay out of sight.

Some bettas will eat a few, as will some gouramis. It's never enough to eradicate them. They will sting a fish, but probably (my guess) at a mosquito bite level for us. Some Hydra species will eat fry, some can't. Some photosynthesize, some don't. I've seen green ones, red ones, orange ones - influenced by diet. There are also size differences with them.

I will will sometimes take a syringe filled with hydrogen peroxide, and shoot them with it from about a cm away. Just a tiny amount of peroxide will kill them. It's a treatment against individuals though, and you'd need more time on your hands than I have to wipe out the creatures in a tank.

 

[MaloK]

I had them in my shrimp tank in the beginning and once the shrimps started to multiply, they all vanished away and never returned. 6 months now without seeing any.

If you keep the nutrients level very low in the water, they have nearly no chances to make it until you add your betta.

Hydras are considered immortal at the moment, ongoing studies have proven some hydras living more than 40 years old in lab setups. They seem to defy aging as we know it. And this can make them nearly impossible to eradicate.

 

[Thermal]

I had them in my shrimp tank in the beginning and once the shrimps started to multiply, they all vanished away and never returned. 6 months now without seeing any.

If you keep the nutrients level very low in the water, they have nearly no chances to make it until you add your betta.

Hydras are considered immortal at the moment, ongoing studies have proven some hydras living more than 40 years old in lab setups. They seem to defy aging as we know it. And this can make them nearly impossible to eradicate.

that's the thing that confuses me the most, I tried to look up if you can just wait for them to starve to death or get eaten. But after reading that they're somewhat immortal? it makes me even more confused as to what happens to them, when other people share their experiences with hydras seemingly "vanishing" after a while? where do they go?

 

[MaloK]

They seems immortal, yes.

But, they can starve to death, some water chemistry can be detrimental to them, many "things" can out-compete them for food, they are often destroyed by other foraging critters.

While they are said to be eating seed shrimps and other micro critters, I saw seed shrimps literally stealing food from their tentacles and cherry shrimps completely destroying them while foraging. This creates adverse conditions that help maintaining them invisible.

Like Gary mentioned, they are probably still there, waiting for their conditions to improve so they can multiply again.

 

[Thermal]

They seems immortal, yes.

But, they can starve to death, some water chemistry can be detrimental to them, many "things" can out-compete them for food, they are often destroyed by other foraging critters.

While they are said to be eating seed shrimps and other micro critters, I saw seed shrimps literally stealing food from their tentacles and cherry shrimps completely destroying them while foraging. This creates adverse conditions that help maintaining them invisible.

Like Gary mentioned, they are probably still there, waiting for their conditions to improve so they can multiply again.

welp, glad to see the other fauna keeping them in place in the meantime

 

[Colin_T]

Hydra are coelenterates and are related to sea anemones. Sea anemones can live forever if they don't get killed by something (fish, people, chemicals, etc).

The old school way of killing hydra was with a 9 volt rectangular battery and 2 lengths of copper wire. You put a piece of copper wire on each terminal of the 9v battery and put the other ends in the aquarium. The battery stays out of the aquarium. It worked great on hydra but messed up some fish. If you put the fish in another tank for 24 hours and then do a water change after using the battery, the battery and copper wire will kill the hydra and the fish can go back into a hydra free tank afterwards. But any new plants you get could be infected with hydra so they should be quarantined before being added to an established tank.