Hydra wars; control, containment of hydra

apistomaster · Post by **apistomaster** » 28 Oct 2006, 13:55

Piease share your hydra war srories about solutions to controlling hydra in a fry raising tank.
Sustitution of bbs with cyclop-eeze has allowed me to starve hydras down to minimal levels. Others swear by blue goramis and paradise fish but this method of biological control is inappropriate in fry tanks,
How have you dealt with hydra infestations in your fry rearing tanks?

aquaholic · Post by **aquaholic** » 28 Oct 2006, 16:00

Larry - I have periodic outbreaks of Hydra as I use a LOT of live Baby Brine Shrimp in my fry tanks. Luckily it is pretty easy to remove. I just run some Copper Sulphate through the tanks, usually without any fish fry present if possible. CuSO4 is much more detrimental to invertebrates than fish and doesnt harm your biological filtration. Free copper is what your after but the toxicity and effectiveness will vary greatly depending on waters pH, hardness and temp. I usually mix up by own solution but you can get some as SNAIL RID/REMOVER if your only after a little.

On occasions where I have had to run copper with fish present I select a test fish (the smallest or most susceptible/frail species the better), put it in a control tank with some hydra present and then slowly increase copper concentration until the hydra die. No need to worry, there is a large gap between what is harmful to the hydra and the fish. You can look up copper toxicity symptoms online of you wish but any observant fishkeeper will know when a fish is having trouble breathing or not looking well. Once I have determined the lethal (to Hydra) concentration, I add to my system. Strongly suggest you leave all filtration running so the copper can reach everywhere the Hydra can. Once Hydra are eliminated, you can water change to remove copper although it precipitates out quite rapidly by itself anyway. Copper is far less toxic at high pH, Hard water or cold temps so it is best to run a simple control test on some Hydra and fish anyway.

I have used this numerous times and on some large systems but suggest you do this on a small scale first if you are unsure.

PS If you use SNAIL REMOVER remedies, disregard the dosage rates mentioned on the bottle, as they are far too weak to remove any hydra.
PPS. Just in case there are some idiots out there, copper can be dangerous so mix with gloves, dont inhale and all the other common sense warnings which should be obvious.

aquaholic · Post by **aquaholic** » 28 Oct 2006, 16:17

Larry,
Just read your other post (before you started this thread) and in that other post you mention plant safe remmedies. I have not used copper with plants since I run all my tanks bare bottomed and keep strong light out of my fishrooms. ie I dont have any plants. Copper is probably okay but I havent tried. Suggest you do a simple trial with plants too.

apistomaster · Post by **apistomaster** » 28 Oct 2006, 16:41

Thank you for your recommendation using copper sulfate solutions for hydra control. I must admit I have never tried it before although I was aware of the option. I'll test it out on a tank and see how it goes. Good advice about keeping the filters operational as they do act as a reservoir for the hydras to quickly reproduce themselves to their former numbers. I'll report my results after I've given this a try. This is not going to an be easy step to take. I want to eliminate the hydras in two tanks containing 2 an 3 week old Corydoras sterbai fry. I would have preferred a less delicate stage or fish to experiment on.

sidguppy · Post by **sidguppy** » 28 Oct 2006, 17:20

I once had a serious Hydra-war going on in my Phyllonemus/lophiobagrus fry tanks.

these cats can be tricky once they start to eat (baby petricola's are much easier) and the best way to "kickstart" them into accepting any food is fresh hatched brineshrimp eggs (artemia nauplii) and microworms.
add a pinch of Hornworth from a pond and within weeks it was like looking at a marine tank with miniature Glass Anemone's.

I tried all kinds of stuff, but the best cure was to get the baby cats on the artificial foods. once the fry was eating de-shelled artemia-eggs and other baby food I starved those Hydra's to death within a month.
I kept the temperature a bit high (26-27'C) to make sure any "Hydra eggs" (or whatever it is they use to proliferate) hatched right away. the newborns also starved for lack of live food.

and I never took any plants again from a pond of course.

apistomaster · Post by **apistomaster** » 28 Oct 2006, 18:15

Hi Sid,
I started these C.sterbai on decysted brineshrmp eggs and then home frozen baby brine but I did begin feeding live brine as well and the rest, as they say, is history. I lacked the confidence in restricting the feedings to decysted bs eggs. I have a 3rd batch just hatching and I may just try the decysted eggs only until the are on staple foods. Usually hydra are more of a nusiance than threat but I have seen some of the sterbai acting as though they had been stung one too many times. Unlike some fish that are free swimming in the water column and apparently evading stings and therefore mortalities, the poor Corys have to sit in a carpet of them on the subtrate, an 1/8 layer of very fine silical sand.

syno321 · Post by **syno321** » 29 Oct 2006, 20:45

I have used a product called Aquari-sol in the past withh many different kinds of fry, in their tanks, and had great results killing hydra without effecting fry negatively. I double the recommended dose for a few days, or until the hydra are gone, whichever is sooner. This is a product that is supposed to "prevent ick", and is also supposed to treat "closed fins,body fungus, velvet and sluggishness". Thelabel says it contains soluble copper salts.

apistomaster · Post by **apistomaster** » 30 Oct 2006, 02:24

I'll take this under advisement. I did just buy a chelated copper solution and copper test kit

aquaholic · Post by **aquaholic** » 06 Nov 2006, 18:49

Larry,
I found a great informative site about Hydra here:
http://members.optushome.com.au/chelmon/Hydra.htm
The author doesnt recommend copper but has some other suggestions. Some of which I have used for fish internal parasite treatmets successfully. How is your Hydra treatment going? I have a science degree but I dont think you need a copper test kit for what your doing. I would make up a sufficiently large stock solution (or use a commercial snail remover) and then use this for your trials. ie if ten drops of stock solution in a 10 Litre tank does the trick then you can directly calculate how many drops required for your real tank.

I almost posted my effective concentrations initially but quickly realised the effectiveness will depend on your softness, pH and temp so decided against this. Far better for you to work this out yourself and less chance of people misinterperating my post and then blaming me for false advice.

I throw in copper scourers (like steel wool only copper for scrubbing pots and dishes) in the sumps of some systems too, a little copper helps reduce white spot I think. Some old timers use copper pennys for same purpose.

apistomaster · Post by **apistomaster** » 06 Nov 2006, 19:28

Hi aquaholic,
You are quite correct that everything depends on the chemistry of the actual water involved. I have yet to find any treatment method that is effective killing hydras that isn't just as effective killing fish. The only method of control that is completely safe is starvation which of course reduces the visible numbers only. A residual hydra population always remains.
Everything from chemical to electrolysis have been cited as effective means but I do not find any method that doe not harm as much as it helps. Starvation is also hard to practice in fry tanks. Changing to microworms from bbs is somewhat helpful. I have been having touble getting microworm starter cultures lately. Hydra don't seem to thrive on microworms as well as they do on bbs. I have had nearly complete losses of one tank of young Corydoras sterbai as they had to cope with the hydra at an age or stage where they are generally very delicate anyway. They could not handle the constant stings from the hydra that were so thick so as to form a mass of green polyps covering every surface of the aquarium interior.
I am going to nuke this tank with a tear down and washing with chlorox bleach. When I set it back up for another spawning I will try not to reintroduce them. I really prefer to have some fast growing plant in my fry tanks for all the obvious beneficial reasons. I use Najas quadelupensis extensively as a utiltitarian plant. I will forego the use of any plants or other unsterilizable materials in the new set up. This was a very large batch. I had several hundred C. sterbai that have been reduced to only about 50 very shakey of the largest strongest fry. I will try to separate them from the hydra when I move them out but many will not be strong enough to survive the move anyway.

aquaholic · Post by **aquaholic** » 06 Nov 2006, 21:14

Larry,
I HAVE used copper effectively to remove hydra with fish present. Baby cories are pretty sensitive but I would expect them to be okay. I was going to suggest vinegar eel as a good BBS alternative but I guess you want something that sits on the ground. Nuking the tank with a chlorine based compound will definitely work. I do this routinely anyway to stop gill flukes and other parasites/bacterial blooms since my fry tanks are so rich in nutrients.

If you use live plants I highly recommend a short soak in alum. A level tablesppon per 5L for a few minutes will remove hydra without damaging the plant too much.

apistomaster · Post by **apistomaster** » 07 Nov 2006, 05:13

I appreciate your suggestions. I have read about them and known about them for 40 years. I have tried them all before. None of them have ever worked. I must have a different hydra species, one that has never read the books and so doesn't know it's supposed to die. I have used alum and have never seen it kill snails or hydras. It kills plants though if you make the solution strong and soak time long enough.I have no idea why none of these things have ever been effective for me but what I'm saying is true. I have used snail rid(brand name), a copper sulfate solution and have tried soaking plants in it at many times the recommended strength. The plants died the snails did not.
I have tried CLOUT before again at several times it's recommended dose. The hydra contract in it's presence but have never been eliminated by it. This animal bears it's name for a reason. I have seen it disappear after months of no zooplankton additions not a very useful strategy in a breeding operation. I have the green hydra which shares with it's marine cousins the presence of symbiotic zooanthellae.

aquaholic · Post by **aquaholic** » 07 Nov 2006, 19:44

Well if others have succeeded and you have not, what do you do....? Most fishkeepers would either keep trying till they get it right or try something new. What is your dosage difference between hydra and cory fry mortalities if you have been unsuccessful? I really cant see hydra being more copper resistant to any vertebrate. And if they are very similar you could dip the pH to increase toxicity towards hydra since hardness is harder to reduce. I dont have any hydra atm but some of my 6mm panda cory fry are handling the strengths used in my last hydra outbreak. It doesnt take long to run a quick trial.

Suggest you try again if copper is not killing your snails/ hydra or alum is not removing them. Alum doesnt need to kill hydra to be effective, just needs to make them uncomfortable enough to dislodge them from plants. A magnifying glass check will suffice if you dont have a disecting microscope. I usually soak plants for 5 minutes.

Logic tells us if snail rid is not killing your snails then it is still not strong enough. Same for clout and hydra. So what if it is already several times the recommended dose? Sounds like you will have to replace your plants though. I am assuming you have pulled out any carbon from filtration if you have any?

I can only tell you what has worked for me and let you and your logic figure out what works best for you. At worst a nuke and restart with clean plants (if you must have them) will definitely work.

apistomaster · Post by **apistomaster** » 11 Nov 2006, 04:48

Logical tell's us to beware of the pitfalls of inductive reasoning.