# [Wet Thumb Forum]-The Hydra are here...I think.



## Mr Fishies (Apr 9, 2006)

My tank is now about 10 days old, and I've discovered pond snails that arrived with the plants, and I have also observered hydra (I think, pic attached to confirm).

The pond snails, may not necessarily be a bad thing, barring population booms.

The hydra, I assume arrived on the plants as well since I've only had fish for 24 hours and been through 2 feedings...posts in other forums mentioned overfeeding.

There's nothing coming up for searches in El Natural for hydra so I have 2 questions.

What can or should I do (El Natural style) about the hydra? I've read cures ranging from pennies in the tank to a tear down!

In the future, what should be done to try and prevent importing critters on plants. I guess my washing was not sufficient. I've read as high as a 1/5 chlorine/water dip. Sounds a bit extreme.


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## Miss Fishy (May 13, 2006)

Dear Fishies, 

I think that Hydra only kill fry, so unless you want to breed your fishes, why not just leave them? From what I've read Hydra are hard to get rid of. 

I actually like all the little creatures that arrive on plants, and find that they do a great job of eating left over food and cleaning the plants. I don't seem to have any problems with over-population. I want some Hydra! 

I give newly purchased plants a Potassium Permanganate bath if I they come from a tank with fish. 

From Alex.


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## dwalstad (Apr 14, 2006)

Hydra, in small numbers, are a natural part of ecosystems and will come on almost any plant, etc. I found hydra virtually impossible to eradicate from a planted tank.

As with algae, the name of the game is control, not eradication. 

Hydra only caused a problem for me when I was feeding my fish baby brine shrimp. Then the hydra started to cover everything in the tank.

If you are feedig baby brine shrimp, the trick is to add only a small number of shrimp. Remember each baby fish can only eat a few shrimp. Once I stopped flooding the tank with brine shrimp, my hydra problems were over. 

I've learned to conserve my baby brine shrimp. Right now, a 1/4 teaspoon of eggs will keep my 50 baby Rainbowfish well-fed for about a week. I keep the shrimp going by small amounts of fry food to stimulate bacterial growth. When the shrimp eat the bacteria so that the water clears, I add a tiny bit more fry food. It usually takes a few days for the water to clear. 

It's a great hatching system. Right now I'm reusing the same saltwater I used back in Dec for a new batch of baby fish. I just filtered out the egg shells and reused the old saltwater.


If the tank is out of control with hydra from "brineshrimp overdosing", you can remove the fish and raise temperature to 105F for an hour. This didn't kill the plants, but did kill the hydra. The other thing that will kill adult hydra is Bausman's tonic. However, hydra lay eggs, so they'll come back in a few months.

I wouldn't worry about hydra.


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## Miss Fishy (May 13, 2006)

Perhaps I do have some Hydra after all, but since I don't breed my fish so don't ever feed baby brine shrimp, there aren't enough to be noticed. Wouldn't they eat any tiny creature 'though, like baby Daphnia or water beetles? I'll look more closely at the plant leaves in the hope of finding a few. 

Last summer I bred some adult brine shrimps for my fish, and now that it's too cold for them to survive outside I'm using the water from their pond for housing shrimp bought from the LFS. I keep the pond in full sun so that algae grow, bring some inside to keep purchased shrimp in until they are eaten, and then put the water back. They like munching on the algae as well as what I feed them. I have a thin layer of sand and shell grits on the bottom of their container, and this apparently provides enough homes for nitrifying bacteria because there are never any ammonia problems, even without water changes. 

From Alex.


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## dwalstad (Apr 14, 2006)

Miss Fishy,

Hydra might eat baby daphnia. However, remember that hydra are attached (not swimming around), so they wouldn't eat that many. 

I've also not had an ammonia problem with my brine shrimp hatching. My theory: the eggs have nitrifying bacteria on the outside of their shells (the shells are probably covered with assorted bacteria from their natural habitat). So I like to leave the old shell casings in the hatchery water. The shells seed the hatchery with nitryifying bacteria and provide more surface area for nitrifying bacteria.


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## Miss Fishy (May 13, 2006)

I looked for Hydra but couldn't find any.









That's a good idea about the brine shrimp egg shells. I bred brine shrimps from adult shrimps from the LFS, and for some reason I never saw any egg shells. Do the dried eggs have thicker/larger shells?

From Alex.


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## Jane of Upton (Jul 28, 2005)

I've kept planted tanks for years now (various methodologies) and I don't ever recall finding hydra. I've now looked in my current tanks, and none are evident. 

Over the years, I've had lots of hitchhikers: snails, planaria, copepods et al, etc. I haven't seen hydras though. I'm wondering if they get eaten readily? I know I used to occasionally see planaria in my large planted tank, but now haven't seen a single one since introducing some Sparkling/Pygmy Gouramis. I attribute it to them, because they seem to spend their whole day RIGOROUSLY inspecting every square millimeter of all the plants in search of live yummies. 

In reference books, I've always come across mentions of hydra as one of the perils of collecting wild-caught live foods from local waterways. There has usually been some stern warning that they can bring disease into the aquarium, and even attack/eat fry. Your photos seem to depict a much, much smaller type hydra. I guess if they're tank-raised (the hydra) there is less chance of bringing in some pathogen that might affect the fish or plants. Hmmmm, interesting. If they're that widespread, then its doubtful that I haven't had them. Hmmmm.


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## Jane of Upton (Jul 28, 2005)

oops, hit post before I meant to....

Anyhow, are you concerned because you've read the same "warnings" I have? It sounds like these little plant hitchhikers are pretty harmless.

Are they everywhere, or just occasional?

Interesting topic.
-Jane


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## Mr Fishies (Apr 9, 2006)

It seems another unexpected visitor may get a free home. The hydra can join the community with the snails and 2 platy (so far) and we'll see if they get out of hand. 

Since I have no plans to raise fry (fingers crossed the 2 female platys are not carrying surprises), I would be more concerned they will get to a point where they are visually disturbing. Right now they seem to be quite localized on one or two dwarf bacopa. (I could wipe most/many out with an external treatment of one or two plants...hmmm).

Jane's post mentions gouramis...long term, this would seem to be the more "natural" way to do things...as opposed to 9 volt batteries and copper wires.

I've just returned after a 3 day long weekend and there is much new growth, flora and fauna. Bigger hydras, much bigger snails (I may be able to get a positive ID on them now) and nematodes (the 1 mm worms on the glass?).

Some new thread algae I had not noticed before. (Uh Oh) Ludwigia that need replanting (the bottoms are turning soft) but there seems to be much root growth above the dying section, and I still can't find dwarf sag or any grassy plants to more thoroughly "carpet" my tank as I had planned, but I need to get more plants in there.

This first aquarium after about 7-8 years is so far very intersting and a fun work in progress...I just hope it doesn't leave me behind.


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## Miss Fishy (May 13, 2006)

Dear Fishies, 

Can you post some pictures of your tank? It sounds very nice. 

From Alex.


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## Mr Fishies (Apr 9, 2006)

Hi Miss Fishy,

Here's a single pic of the overall tank from a week back. The lights clicked off tonight about 5-10 minutes before I signed on, I was going to trun them back on to take a few pics, but the water was quite dirty suddenly. The ludwgia or vallisneria seemed to shedding "dust" into the water. It almost looked as if I had stirred some of the bottom up. Is this is a normal? 

---

So far, I've really made not atempt at any aquascaping, just threw a bunch of plants in to see what will do best. 

Since I took this pic July 31, the cabomba has kind of yellowed at the bottom, but has sent roots out all over the place on many stems. Not sure what's happening there.

The ludwigia still needs some more soft stem cut off and replanting (and snail egg removal).

The bacopa is doing nicely, some new growth and looking quite healthy green.

The vallisneria is doing very well. I've noticed about 6-7 new plants along 3 runners...and that's what I can see. It's invading the ludwigia.

A lot more plants are needed and will be added when I can find some suitable foreground plants in the LFS.


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## Miss Fishy (May 13, 2006)

Dear Fishies, 

Your tank looks very nice. What is that wide-leaved plant in the foreground? Does it stay that size? If it stays smallish, maybe you could use it as a foreground plant? I think it would look lovely if you grew a whole lot of them along the front. They make a nice contrast to the stem plants. 

Have you tried leaving the Ludwigia to grow aerial roots into the substrate? Sometimes I find that the bottom part of Ludwigia stems die off, but if I just leave them alone the roots further up the stem eventually make it into the substrate. It seems to dislike being disturbed. 

From Alex.


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## Mr Fishies (Apr 9, 2006)

> What is that wide-leaved plant in the foreground? Does it stay that size? If it stays smallish, maybe you could use it as a foreground plant? I think it would look lovely if you grew a whole lot of them along the front.


That's actually a small sword plant. Not doing so well either. I completely fogot to mention it. I'd be in trouble fast if there were more and they ever took off. I am trying to find something to fill in the front of the tank...dwarf sag or something short with broader leaves, as you said in contrast to stem plants. Not too sure the cabomba is too happy, so I may have more space to fill. Seems to be hard to find nice foreground plants in the LFS I've been to/know of.

Thanks for the tip about the Ludwigia, I had already removed the soft browning bottoms and replanted with the stem as shallow into the soil as possible to get the roots in. There are a few others I was thinking would need the same treatment...I'll leave them to their own devices.


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## Miss Fishy (May 13, 2006)

I found some Hydra in one of my tanks today! Yay! I was looking at a stem of _Crassula helmsii_ when I noticed what looked like a tiny fragment of _Nitella_ (a type of macroalgae that I grow in my tanks) growing on a leaf. When I looked closely, I saw that it was moving! Then I saw five others, about 5mm in length, each sitting on its own leaf and waving slowly looking for food. Woohoo!

From Alex.


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## Miss Fishy (May 13, 2006)

I just found an interesting website about Hydra. Here is paragraph from the site about how Hydra move around:

"After a few moments the hydra spontaneously contracts into a tiny spot, a mere fraction of what it was, and then slowly extends itself in a different direction. Patience will allow you to see all of the varied forms of locomotion the hydra uses to get about. It may "walk" with almost imperceptible slowness along the substratum, clinging by its base with a sticky mucous. It may parachute to the bottom with outstretched tentacles, there to feed on organic debris. It may rise again like a hot air balloon by generating a gas bubble at its base. It can hang by its base from the depression of the water surface and walk or flow with the current. It can bend its tentacles and inch along by alternately attaching tentacles and base to the substratum. By moving its base entirely over, it can progress by somersaulting along."

From Alex.


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## dwalstad (Apr 14, 2006)

Great website!

Thanks for posting it. I didn't know that they moved from one place to the other.


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## Miss Fishy (May 13, 2006)

They must move around quite a lot. I have found many more now that I know what to look for (I didn't know there were green Hydra so I mistook them for algae), and they never stay on the same leaf for more than a few hours. They are very interesting. I saw some with tiny buds growing on their sides, and when I poked one carefully with a stick, it retracted into a tiny lump, only to extend again a second later when a Cyclops swam past. 

From Alex.


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## Chris S (Feb 27, 2006)

Hello! Old post, but interesting none the less! I have had a hydra problem in the past. I went to the LFS and described small anenomes in my freshwater tank and traced them back to introdicing a plant that i collected locally . They hitchhiked in. The LFS guy mentioned that a blue gourami would clear them up. I bought one and it did! I fed him almost nothing and in a week there where no more hydra. I watched him pick them off one by one and always constantly looking for more.
This was a hydro problem. They where totally everywhere! But I have no seen any for years.


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## dwalstad (Apr 14, 2006)

Purchased plants often have hydra attached. Unless you're constantly adding brine shrimp or daphnia to the tank, they shouldn't cause problems.

I consider them an interesting and harmless part of aquarium ecology.


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## Miss Fishy (May 13, 2006)

My green Hydra are still going strong, especially in my 68 litre tank. There are so many on the front glass that I can't use an algae scrubber for fear of squashing them! I now clean the glass with a razor blade, and they just drop off the glass and lurk on the plants until I've finished and then they make their way back onto the glass. Some of them are more than a centimetre long! 

From Alex.


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