Hydra in fry tank

Eric1 · Post by **Eric1** » 28 May 2006, 03:48

I found a hydra in my fry tank. I removed them and I am wondering if there is a way to keep them from returning? I have never seen them before now.
Thanks
Eric

worton[pl] · Post by **worton[pl]** » 28 May 2006, 09:31

Hey,

Hydras are really cool, little critters.
They are not any danger for bigger fish - they can only catch a tiny fry and even in that case they are not so good in catching fry they could eat whole batch.

You can put them in small jar, keep changing a bit of water and from time to time feed them with flakes (you have to watch if they are able to catch it) - when you get lucky you can observe their whole reproducing cycle - which is really fantastic (you will be able to see some free-swimming medusas!).

Regards.

Post by **medaka** » 29 May 2006, 13:52

Hi Eric

A few years ago, I found that I had hydra in quite a few of my tanks. What did surprise me was that for the first two weeks or so after my fry have hatched, they are housed in small tanks that have no substrate, just having black bases to them. One day I noticed a hydra on a side panel, approximately 5mm up from the base, and on further inspection I found that the base of the tank was infested with hydra all about 3 to 5 mm in body length. I missed this infestation due to these Hydra were black! And seem to prefer the base of the tank. I hurriedly rang a friend of mine that was using the same source, where I collect my daphnia. A couple of hours later he rang me to say that he also had found â??blackâ?? hydra on the base of some of his tanks. As we both had never come across this â??blackâ?? hydra before, it is something that I thought should be mentioned.
On the tanks that I could thoroughly clean out and â??sterilizeâ?? I did, luckily I had some Betta burdigala young and where possible I introduced these to the tanks that sterilizing was not an option. On other tanks I used Colisa chuna (honey gourami) young. These fish will eat hydra
I have found over the years that using natureâ??s answer, where possible, is a better way of eradicating hydra, and I must say young anabantids seem not only relish hydra, but they also seem to develop quicker, when feeding upon a hydra infestation.

worton[pl] · Post by **worton[pl]** » 30 May 2006, 00:06

Hey Medaka,

are you sure that these animals weren't from bryoza group? Hydras usually do not breed fast enough to infested whole bottom of a tank in two weeks.

And bryoza's really like dark places :).

Regards.

Post by **medaka** » 30 May 2006, 15:15

are you sure that these animals weren't from bryoza group? Hydras usually do not breed fast enough to infested whole bottom of a tank in two weeks.

They looked like Hydra to me, although I must say that I am not familiar with bryoza.