hydras: the friendly freshwater anemones???

topic posted Wed, August 9, 2006 - 2:00 PM by  katrinka!
hello all!
a while back i noticed a tiny hydra attached to the tip of a leaf in my tank. i searched out info on them and it there didn't seem to be much in the way of info on effects to resident fish but then it seemed to have disappeared for a few weeks. just this week i noticed atleast 10 - 12 hanging on to plant life and on the side of the tank. they are hardly noticable- so tiny- but do they pose a threat to my fish? will they take over the tank eventually? is there anything that i can do to treat the tank without disrupting the rest of the ecosystem?
i would be grateful for any advice!!! thanks!
posted by:
SF Bay Area
  • Re: hydras: the friendly freshwater anemones???

    Wed, August 9, 2006 - 2:09 PM
    I found this site.

    All I can recall about them is, they are dangerous for fry. If you are breeding fish, as I do, then they are a serious threat and the tank should be nuked.
    • Re: hydras: the friendly freshwater anemones???

      Wed, August 9, 2006 - 2:17 PM
      interesting that gouramis prey on them- i recently lost one of my dwarf gouramis- i miss him :-( and this week is when i noticed all the hydras...
      • Re: hydras: the friendly freshwater anemones???

        Wed, August 9, 2006 - 4:18 PM
        WOW, I haven't ever seen one in an aquarium, and I have peered into many a fish tank, thousands of them literally, and have never seen a single hydra, kinda cool but if you raise fry, very uncool, i have heard of people having them though. The tiniest bit of copper sulfate will knock em out without having to do anything to the tank. I saw on the link they reccomended using salt and taking out all the fish, which generally isn't practical, or using clout which is actually a pesticide that is somewhat tolerated by fish, but it is literally an insecticide. I have used it a few times personally, It will generally cause sterility in small fish, It works great though on large fish, Koi, cichlids, that kind of thing and is super effective in cichlids with hole in the head disease. For something like hydra though I think it would over kill. One drop sea chem cupramine per two to three gallons of water would most likely knock em out make sure you don't have any snails though it tends to kill them too. If you have very hard water you might have to go to a full dose of one to two drops per gallon as the copper likes to bond to other minerals especially sulfur and calcium. Still a very cool thing to see, if you have any photographic skill and a macro lens take some pics to share!
        • Re: hydras: the friendly freshwater anemones???

          Wed, August 9, 2006 - 11:56 PM
          Here's a cool pic I found:

          BC, are you a fish doctor? You really should be. This hobby needs people like you.
          • Re: hydras: the friendly freshwater anemones???

            Thu, August 10, 2006 - 8:44 AM
            Wow, cool! Katrinka, what kind of set-up do you have, and how do you think you got them?

            If they are so rare in an aquarium, why bother to eridacate them? They sound pretty harmless, and if you are breeding, then why not set up another tank for that purpose and let the hydras do their thing?
            • Re: hydras: the friendly freshwater anemones???

              Thu, August 10, 2006 - 10:04 AM
              I was reading through some old issues of TFH circa 1974, don't ask how or why I have them and came across a reference to them, apparently they breed asexually, and can over run a tank VERY fast, so whereas one or two of them or even a few more might be a really cool thing, I don't think I would want thousands of them in a tank, Unless of course you were really into hydras.

              Actually Shannon my nickname when I managed the last three shops became "doctor fish" just by default. I owe a great deal of what I know to a wonderful women that owned a shop in Denver, she recognized that I already knew a great deal about fish diseases, and encouraged me to learn more so I did, I read many college marine biology books, books on fish ecology, and fish husbandry and got out of it what I could, and then went on to specialized veterinary books on fish diseases and any laymans books I could get as well. I learned as much as I could from what references I could get my hands on about nutrition,physiology and anatomy, it helps to know all of that stuff because many times what looks like a disease is simply a matter of water quality as we have all said in here many times, and often nutritional factors come into play as well, and even the basic anatomy of a fish has a certain aspect to do with various diseases or conditions they may come down with, Take gold fish for instance, fancy gold fish in particular are the result of almost a millenium of selective in breeding to acheive the twisted and contorted shapes we see in them today. While these selective mutations may look pretty on the outside to goldfish fanciers, it really has twisted the gut of the fish around in ways that are beyond belief, their intestinal tracts are totally twisted, their swim bladders are completely out of whack, and what this does is make a fish that is suceptible to a bunch of diseases and conditions that a wild carp wouldn't have, Something as simple as feeding brine shrimp to a fancy goldfish can prove deadly. Knowing the various mechanisms of parasites is also good to know and being able to tell the difference between a fungal infection and a bacterial one is a nice thing to be able to do as well although in many cases very difficult. Many times what we think is bacterial in fresh water fish turns out to be fungal and responds to a totally different set of treatments. I know that sometimes I get frowned on because I will reccomend a treatment that sometimes seems like its treating different things when only one problem is present, I will generally reccomend the use of salt with and treatment, salt being more or less non-toxic to fish is also a natural fungicide, so it helps prevent fungal infections in necrotic tissues where a bacterial or parasitic infection is present. Just like people often its not the initial problem that ends up being the cause of death but rather a secondary and oppurtunistic infection that kills. When I make reccomendations I try and take the whole picture into context, water quality first and foremost; what is the stress factor that is most likely to cause the inital disease, what will the likelyhood of secondary infection be, what are the other inhabitants of the aquarium, etc... Thanks for the great compliment! I really do enjoy the hobby and I really want people to have happy healthy fish and I am sure that all of us do, otherwise why would we even be here?
              • Unsu...

                Re: hydras: the friendly freshwater anemones???

                Thu, August 10, 2006 - 11:39 AM
                Selective breeding to satisfy the bizarre whims of us humans certainly hasn't helped some of our fellow earth inhabitants. Besides the contorted goldfish that you mentioned, there are dogs with large folded wrinkles of skin and poultry with large top heavy plumes of feathers. I raise homing pigeons, and I would guess that these birds are one of the few species that we have helped in health and vitality....since they are bred for speed, endurance, and homing ability.

                BC.....The extent to which you devoured the fish husbandry and disease books reveals the passion you have for the hobby. When I was a teenager, I had an outdoor kiddie pool fish pond which I stocked with game fish that I caught at ponds. I loved creating an underwater world for my fish with waterlillies and rocks. The pump and sand filter that I contructed worked quite well. I've just gotten back into aquariums recently, so it's sort of like starting all over again. I know many others besides me appreciate what you share about what you've learned.
                I've learned from many of you here.
                • You guys are awesome!!!

                  Thu, August 10, 2006 - 12:09 PM
                  nice picture of the hydra! i'm not sure that my camera has that macro capability :-(
                  i had always wanted to have a fish tank and was never settled in one place for long enough. back in march i decided to go for it and it has been going thru cycles of improvements ever since. there is a science to it and it fascinates me. i love to just sit and stare into the tank of endless moments. it has become a form of meditation for me. i suppose that i wouldn't have noticed the hydras if i didn't spend so much time studying this little world.
                  i'm thinking that they may have hitched a ride on some of the plants that i added a month or so ago. maybe the water lilies or possibly in the bloodworms? i think i will wait to treat the tank because i am not attempting to breed any fish at the moment.
                  thank you!!! and thank you BC!!! this tribe proves to be a source of invaluable shared information!!!
              • Re: hydras: the friendly freshwater anemones???

                Wed, August 16, 2006 - 11:30 AM
                You are welcome for the compliment, but it isn't just that, it is a fact. :)

                So seeing as how you are a great fish diagnoser, I was wondering which fish stores you'd recommend in SJ? I went to one called Dolphins (can't remember the full name) and I thought it was good since they quarantine. Anything in Wats/SC are mediocre at best. Also, if they sell plants, that is a great plus.

                I know this is off topic. Sorry to the OP, but I'm desperate for some good stores that aren't hours away.
                • local mom and pop stores

                  Wed, August 16, 2006 - 11:51 PM
                  unfortunately i have only found petsmart for the plants~ just planted some dwarf water lillies in our outdoor set up- hopefully the racoons won't eat them this time... :) (they chewed up the water hyacinths and my coi last time)
                  i would much rather support a local mom and pop store but have found none~ anyone want to give some tips?
                • try joining a fish club ,where you can go in with other people to do purchasing with an internet shop(these places while thier prices are comparable with most shops they rape you on shipping)The more you ship the less the price in freight
  • Re: hydras: the friendly freshwater anemones???

    Thu, March 8, 2007 - 10:52 PM
    Joining the club here.

    I was watching the fish with my little girl and I noticed that I have tons of hydra clinging to the glass. I also have a neon dwarf gourami which is supposed to eat these hydra but apparently not. Its like they appeared overnight. I also have lots of white specs floating around in the tank.

    All I can say is...WEIRD.
    • You might just have the mysteriou white spring worms they tend to shw up tanks in the spring for some unnown reason and disapear as quickly as they showed up, often times they get confused, But it you really do have hydras, and its not common, they most likely came in with a live plant, or hitchhiked on a snail. hydras repreoduce asexually so all it takes is one, and basically you end up with a gazillion clones in your tank, a gourami of anysort will generally gnaw on them but they don't usually wipe them out, Botias seem to really go after them but most are somewhat agressive, Clown loaches being a botia are an exception and just might eat them all, Clown loaches just FYI are particularly fond of pond snails if you or anyone else ever has a massive out break of those, Clown loaches need to be in groups or three or more though, being highly social fish, Also botias of any sort do this wierd sleeping thing where they look dead, sometimes even rolling over as they sleep and drifting with the current in your tank, I think they just like to freak us out though.....

      If you have hydras and want to get rid of them, any type of anti parasite medication with wipe them out very easily, maracide works well if you have scaless fish, or even plain old cheap noxich.

      If you have the white worms which I suspect you do since you said you have whate specs floating in the tank, best thing to do is just ride it out, since they aren't parasitic and they disappear as rapidly as they showed up.
      • yes they hitchike on plants ,working in the twin cities i saw alot af hydras ,both in the shops and the distributer up there,knowing that the distribiter got their plants from a local greenhouse they were comming from local waters (the greenhouse water supply is the apple river in wis.).
        like BC said harmless unless your breading,however a trick that one of the shops that i worked at was to put a penny in the tank for a couple of days.It gennerally wiped out the hydras,but you had a tiny spike in amonia(could never figure this one considering copper generally dosnt affect the bacteria).the spike wasn't enogh to affect the tank.
        • A penny would leach out a tiny amount of free ion copper, not bonded like a medication, Meds are either bonded to sulfate, or chelated with citrate or any number if other oxidizers, Could be and this is just and educated guess that the free ion copper, could have just caused disattachement from some other agent in the tank that ammonia was bonded to, copper has a pretty strong naturally positive charge, so it could in theory break a weaker ionic bond, Most of the of the time ammonia in an aquarium is bound into a chloride bond, which is very strong, but since we generally use a dechlorinator it breaks that bond, If in aquarium where no dechlor has been used or very little (most people overdose the stuff) then this bond would not be presnt and ammonia would be bound with another ion, and the charge of the copper could free it up and you would end up seeing it on a test kit as a small ammonia spike. Just a guess.....
      • The reason I suspect they are hydras is that they are a little greenish and have several tentacles off the tops. Not really white. Maybe I have both? I will have to check again when I go to turn the light on. I have a boom of snails too. I added live plants a month ago and several days afterwards, I noticed a snail (but no hydras/worms til now). I think I have 20 now. Most are clear or greyish but a few are bright orange/gold. BUT if they ARE hydras and came in on the plants, wouldn't they have shown up before?

        As for the worms, if they are, could it be due to a minor rise in temp? All of a sudden, my tank is at 83 when it is usually at 81. I turned down the heater. Also, the pH is up to 7.6 when it is usually 7.4
        • Re: hydras: the friendly freshwater anemones???

          Fri, March 9, 2007 - 10:25 AM
          when was the last water change?no3 is pretty well linked with ph..if no3 is high ph starts to drop(at least in my expierience)
          • Re: hydras: the friendly freshwater anemones???

            Fri, March 9, 2007 - 11:15 AM
            Correct on all counts, NO3 forms nitric acid at higher concentrations, also higher temps hold less oxygen, so it could be a double effect, warm water will decrease in pH and high NO3 with lower the pH as well, So chefpablo it's not just your experience its actual science.

            Sounds like you definately have hydras from the description, Even though I have never actually seen one in person, I have seen pictures, and you have described them fairly well,
            • So I was thinking of doing the "penny in the tank" trick to clear out the hydras, Will this have any effect on the snails (or my cory cats and Gourami)? I wouldn't mind if it killed off my snails, though. Otherwise, I will have to get a loach to eat the snails.

              The white specs are very VERY numerous too and I have little half circle looking things on the leaves of the plats as well as what looks like air bubble under the leaves of one plant (maybe they are snail eggs?)....if I do have white spring worms as well as hydras, how long til the worms go away? days, weeks?

              So many questions......
              • umm get a second opinion from BC about the penny trick, its been 10 years since i did it and im pretty certain we used RO water for our changes and we did them daily.I know your fish will be fine i'm more worried about your bacteria bed.

                the bubble under the leaf ,does it kind of look like clear jelly? if it does then yup thats snail eggs
                • Re: hydras: the friendly freshwater anemones???

                  Sat, March 10, 2007 - 8:52 AM
                  I'd probably just use a lite does of copper sulfate, 1-2 drops per 5 gallons of water, Its lite enough it won't even phase the catfish and probably won't do much to the snails, but pretty sure it would be enough to wipe out hydras, You could go as hi as one drop per two gallons but no higher with scaless fish. Or a 1/4 -1/2 strength does of "Clout" would work as well. With medications more is not better, Since you aren't using meds in a therapeutic manner you definately want to go with as weak a does as possible, COurse you might want to try the penny thing, just make sure they are nice and shiny ones, Old ones have god only knows what on them....

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