The Shrimp Vector

badflash · Post by **badflash** » Mon Dec 18, 2006 7:31 pm

I have a tank that I am breeding some unknown species of Neocaridina that I received by mistake in both a load of Amanos and a batch of Ghost Shrimp. Today I looked in this tank and saw a colony of small hydra. I was astonished because I add new species very carefully and NEVER add untreated plants or water when adding new species. In this case the shrimp had spent a week in 2 separate aquariums before I noticed that they were not what I had thought.

The wisdom of the old addage "the best fertilizer is the gardener's shadow" really strikes home. I looked in the tank with the ghost shrimp and found no hydra. I looked in the amano tank and found them! If hydra were not a threat to baby shrimp, I'd be tempted to keep them. I noticed there are no ostracods in the tanks with the hydra.

Anyway, the java moss is now all treated with Potasium permanganate, rinsed, neutraized, and back in the tank. I'll be watching for those amazing jellies, but I caught them before they got carried away.

My guess is that one was attached to a shrimp when I move it, and it only takes one.

Neonshrimp · Post by **Neonshrimp** » Mon Dec 18, 2006 8:43 pm

That is a scary situation

! Thanks for letting us know how to deal with it

iturnrocks · Post by **iturnrocks** » Tue Dec 19, 2006 11:44 am

I had hydra in one of my fairy shrimp hatches. I havent seen any for a while, but it was very interesting to watch them catch tiny critters. All the ones I saw were attached to the walls of the aquarium, but then the largest animals in the tank were fairy shrimp, and I doubt a hydra would be successful latching on to one of them. If youve used any of my dirt, its possible they could have come from there. I dont know the life cycle of the hydra, but I assume its similar to fairy shrimp and the like, since they appear in vernal pools. Perhaps their "eggs" or whatever attached to the glass in a tank and survived a "dry phase" and then hatched the next time water was added. I would imagine a hydra egg would be quite small, and would require a thorough cleaning if they leave them attached to the glass.

iturnrocks · Post by **iturnrocks** » Tue Dec 19, 2006 11:48 am

Just did a quick search and found this:

Hydra reproduce in the summer months. Most reproduction is asexual involving a process termed budding, in which a new hydra develops as a bud from the parent column (see species illustration). Buds later break free, but are genetically identical to the parents (clones). Under favorable conditions, hydra may possess several buds at various stages of development. Sexual reproduction is usually confined to late summer. Ovaries develop as oval swellings near the column base, while testes form as conical projections higher up. Hydra oligactis is dioecious , with males and females occurring as separate individuals. However, most species are hermaphrodites, the testes and ovaries developing on the same animal. Sperm swim out from the testis and enter the ovaries of other individuals. Ovaries each contain a single egg. Once fertilized, this egg develops a protective ornamented shell and frequently enters a stage of arrested development or dormancy. When favorable conditions return (often in the following spring), development resumes and the young hydra develops directly without a larval stage.

It mentions the dormancy state, but doesnt say whether the egg can adhere to something or if it just falls to the bottom.

badflash · Post by **badflash** » Tue Dec 19, 2006 8:27 pm

I've never mixed the triops with any other tanks, so I doubt that was where it came from. I followed the "vector" back to the tank where the shrimp had first been and found hydra. I'm sure they were introduced with the new shrimp, even though I didn't move any water other than what was on the shrimp. I always rinse new shrimp off with new water before putting them in the regular tank, so there must have been some polyp cells or a little hydra on one of the shrimp. The shrimp were the only communication between the two tanks.

They are awsome to watch snatching ostracods. I'm not sure how effective these would be against baby shrimp or crays, but I don't want to chance it.

iturnrocks · Post by **iturnrocks** » Wed Dec 20, 2006 7:51 am

I havent seen any hydra for a few years now. I have some green single stem things that stick off the side of my tank, but I assume its some kind of algae. Sometimes when Im watching really close it looks like they move, but it could just be a current caused by a fairy shrimp swimming by.

YuccaPatrol · Post by **YuccaPatrol** » Wed Dec 20, 2006 8:00 am

I have had just a few outbreaks of hydra over the years. Every single time, they have appeared, stayed around for a couple weeks, and then were not seen again.

I'd suggest nothing more than an increase in water changes and some patience to wait it out.

Neonshrimp · Post by **Neonshrimp** » Wed Dec 20, 2006 8:39 am

Thanks for the tips. Along with the water changes I think you can also remove the accessible ones with a turkey baster or straw for a quick solution if you have young animals in the tank

YuccaPatrol · Post by **YuccaPatrol** » Wed Dec 20, 2006 8:47 am

In fact, once I realized that they were usually a temporary occurrence, I enjoyed watching an interesting new critter for a while.

Of course, I am weird like that. . .

Neonshrimp · Post by **Neonshrimp** » Wed Dec 20, 2006 8:51 am

Actually I would one day like to set a little tank aside just to observe and study these cool looking yet pesky little guys. Wait, does that make me weird....

badflash · Post by **badflash** » Wed Dec 20, 2006 6:37 pm

YuccaPatrol wrote:Of course, I am weird like that. . .

Aren't we all, otherwise we wouldn't be here.

When I was in high school many moons ago, I did a science fair project on hydra. They are way cooler than you know. Hard to believe a bag of jelly can be so complex.

I had big ones and fed them fresh hatched brine shrimp. They multiply like crazy when they get all the can eat. They can reproduce by budding or sexually. They also can move..

Neonshrimp · Post by **Neonshrimp** » Wed Dec 20, 2006 8:18 pm

Cool... Thanks for the info on them. I guess all animals are interesting in one way or another

iturnrocks · Post by **iturnrocks** » Wed Dec 20, 2006 9:09 pm

From http://www.microscopy-uk.org.uk/mag/artdec04/dwqx5.html

iturnrocks · Post by **iturnrocks** » Wed Jan 03, 2007 10:03 am

I asked a question to someone who might know (with the intention of wondering if Hydra eggs might stick to the glass on an auqarium or perhaps the substrate of a tank):

I was wondering if a hydra egg can attach to a plant stem or
if they always just fall to the bottom of the pool.

Julian Cremona, Head of Centre
Dale Fort Field Centre
Dale, Haverfordwest SA62 3RD
Tel: 01646 636205 Fax: 01646 636554

And I got this response today:

As an example of the cnidaria they do have sticky egg cases. So although they typically drop to the bottom (ideally to survive winter, etc) they could just as easily get stuck on substrate on the way down but this would be accidental, I have not heard of any incident where they deliberately attach eggs.

zwergkrebszuechter · Post by **zwergkrebszuechter** » Wed Jan 03, 2007 1:26 pm

Why worrying about Hydra? In Germany we have a native snail, that can eat all hydra in a tank in a few days, even it is hundreds of them. It is called Lymnea staginalis. Maybe there are snails like that in the USA, too?