Are Hydra's A Danger?

[Holding2k9]

I recently saw and removed a Hydra today from my C.orientalis tank.
i want to know about these things and if they cause harm to my newts?

i read a scientific article that stated they obtain a sting in their tentacles?

write back soon.

Tom

 

[SludgeMunkey]

They are only dangerous to species with exceedingly small larvae. The biggest risk is how they can strip tanks of daphnia and brine shrimp faster than the larvae can eat them. They are harmless to adults.

Good news is, if you have Hydra in your tank, you have OUTSTANDING water chemistry.

 

[RitchieB]

Hate to be a pain but saw this on the net somehwere

"Hydra are sensitive to copper, so you can eradicate them with a copper-based disease medication. They tend to thrive in dirty tanks."

So perhaps they are not a sign of good water quailty. Sound interesting though

 

[Holding2k9]

Well Someone Let Me Know ...
is it good or bad water?

 

[RitchieB]

Found this on a FAQ somewhere. Hope it helps : )

I have some small anemone-like things stuck to some rocks in my coldwater set-up. They're 1-2cm long and semi-transparent, with long dangly tentacles. What are they, and can they harm my fish?
Your tank is infested with Hydra, a type of freshwater coelenterate related to marine anemones. They are usually found in ponds, but are sometimes introduced with plants or livefoods.

Hydra are predators and usually feed upon small zooplankton like Daphnia. Their bodies and tentacles are equipped with tiny harpoon-like stinging cells called nematocysts with which they spear passers-by. They rarely do large fishes any harm, but can sting and catch very small ones.

Hydra are sensitive to copper, so you can eradicate them with a copper-based disease medication. They tend to thrive in dirty tanks.

 

[SludgeMunkey]

Hate to be a pain but saw this on the net somehwere

"Hydra are sensitive to copper, so you can eradicate them with a copper-based disease medication. They tend to thrive in dirty tanks."

So perhaps they are not a sign of good water quailty. Sound interesting though

That quote is misleading...hydra, much like daphnia are very sensitive water quality indicators. "Dirty Tank" is a very general term and can mean anything from you have algae growing on the glass to there is 10mm of feces on the bottom. Water quality refers to ammonia, nitrate, nitrite, hardness, TDS, and dissolved O2.


As for using copper based chemicals to remove hydra, do not do this. Copper is fatal to caudates and causes the hydra to "cyst" up. As soon as the copper is gone, they are back.

 

[Azhael]

Agreed. What a lot of people consider a "dirty tank" has nothing to do with water quality. A tank can be full of algae, microorganisms and dead material and be a lot healthier than a crystal clear, perfectly clean tank. In fact the presence of microorganisms is as already mentioned a very good indicator of water quality.

 

[RitchieB]

Point taken

 

[cgarza7]

There is no chance that hydra can sting the gills of axolotls? I thought maybe these gills could be sensitive to the stings.