Hydra!

[Twelve]

I freaked out yesterday when I discovered these strange organisms in my tank. After doing some research, it seems that they are hydra. There's not a lot of them. I can usually only see 2-3 at any given time.

My question is: Do I need to worry about them?

They are in my 10g with my frogs and some mystery snails. I have a bunch of anacharis growing in the tank, which seems to be the hydra's favored location to attach themselves.

Also, how did I get these little things? I just purchased the mystery snails online and they were shipped from a few states away. Could the hydra have hitched a ride on a snail?

 

[Spclk1981]

What are they? I have never heard of them (but I am new to this).

 

[Hound]

Hydra can hitch rides on quite a lot of things so long as they are wet. Hydra are more a pest than an actual threat in an aquarium so long as you aren't trying to raise fry. Of the remedies for removing them is to raise the tank temperature, but I'm not sure if your snails and frogs would like to be in fairly hot water long enough to kill the hydra. Another option would be to add a dwarf gourami to your tank. They are known to eat both hydra and young snails.

 

[OrionGirl]

Hydra in great numbers is also an indicator that the tank is being overfed. Reduce the uneaten wastes (feed less, make sure what you do offer is eaten, clean more often) and the number of hydra will be reduced.

 

[Swimfins]

um what are hydra? what do they look like? Pwease?

 

[geoffgarcia]

generally hydras look similar to this:

however I get the distinct impression they are referring to this one:

Hydra - a little Aquarium Monster
Hydra are small aquatic invertebrates belonging to the order Hydroida, in the class Hydrozoa, phylum Cnidaria. This is the same phylum as the marine jellyfishes, corals, and sea anemones. Only a few species that belong to this phylum occur in freshwater due to the fact that they evolved in the sea. The body is a thin cylinder with several tentacles extending from the mouth (Five to seven tentacles are typical).

The name, Hydra, is derived from a monster in Greek mythology. One of the 12 tasks imposed on Hercules was to slay the Hydra of Lerna. It had nine serpent-like heads, one of which was immortal. So potent was its venom that even its smell was fatal to those who passed too close. Worst of all was that for every head Hercules cut off, two more grew in its place. He finally triumphed by cauterising the wounds with a firebrand as he chopped away. Just like the legendary monster, a single hydra may be cut into many pieces and if each piece contains a portion of the two body layers, ectoderm, and endoderm, it will develop into a complete animal.

 

[Twelve]

Okay, thanks for the replies

I won't worry for the time being. Two or three hydra, I can handle. When they start multiplying in huge amounts then I might be concerned!

I plan to do about a 40% water change twice a week. The tank just finished cycling this last week, so this is the first week that I let up on the water changes -- I was doing them every day prior to that.

I'll just feed the frogs less and maybe the little hydra beasts will go away on their own!

 

[Swimfins]

well, must say fsacinating...thanks Geoffgarcia.

Apparently, to rid of them you need just to keep the water clean, and perhaps clean your equipment in a solution of chlorine bleach.

 

[russjet]

how big are they
couldnt you just syphon out any you see when you waterchange
do they pose any health risk to the fish (take it as no according to an earlier post sorry)

wonder if i can keep them alive

 

[daveedka]

I did extensive research a while back when I found a few in my tank. There are about 400 different ways that people claim you can kill them and about 4000 people who will argue with each method. Things that I did find out are:
1. as said they only populate badly in a food ridh tank
2. Among the ways mentioned to kill them were Red Ramshorn snails, Since you already have snails maybe adding a few ramshorns won't be a problem. I don't know if it will work well, since the tank I had them in also contains fish that eat red ramshorn snails
3. the claims that gourami's will eat them are pretty consistant, although I never reccomend buying a fish just to fix a problem, only reccomended if you wish to own a gourami long term
4. Hydra will get as big as 3/4" long according to my research, and will eat very small fry if they can catch them. Other than that they are fairly fish harmless.
If you break them in half you will get 2 hydra, so trying to crape them off is risky at best.
5. Most other cures I read about are things I don't want to do to my tanks. i.e. harsher than I like and riskier than I like.
6. most importantly if you Google HYDRA you will get everything but these little creatures. GOOGLE "aquarium Hydra" and you will get much better results.

BTW I have no idea where my hydra went, or what killed it. It just left. I imagine it was probably my juvie Firemouth as he seems to eat anything that moves as a rule. I only saw it when life caused me to skip my weekly maintenance, and haven't seen it since.
dave