Hydra

[Chick-In-Of-TheSea]

Hi guys. I believe I have hydra. Seems it’s filter feeding, perhaps helping with water clarity? I think it’s kinda neat.

Do I need to know anything specific about hydra? Any downsides to having it in the tank?

 

Edited September 27, 2022 by Chick-In-Of-TheSea

[DiscusLover]

On 9/27/2022 at 9:58 AM, Chick-In-Of-TheSea said:

Hi guys. I believe I have hydra. Seems it’s filter feeding, perhaps helping with water clarity? I think it’s kinda neat.

Do I need to know anything specific about hydra? Any downsides to having it in the tank?

 

Hydra will kill shrimp and fish fry. If you want to kill hydra no planaria will work well removing hydra.

[Katherine]

https://www.aquariumcoop.com/blogs/aquarium/hydra

This ACO article mentions snails eating them, which I'm pretty sure is what happened in my tank. My fake rock tower was covered in algae and I'd noticed quite a few things that look just like your video. Over the course of a few nights one or more of my nerite snails removed 98% of the algae and I haven't seen a hydra since.

[Chick-In-Of-TheSea]

On 9/27/2022 at 1:08 PM, DiscusLover said:

Hydra will kill shrimp and fish fry. If you want to kill hydra no planaria will work well removing hydra.

Will it hurt adult fish?

[DiscusLover]

On 9/27/2022 at 10:20 AM, Chick-In-Of-TheSea said:

Will it hurt adult fish?

Maybe small adult fish but other then that their stings wont affect other larger fish

[Biotope Biologist]

Looks like hydra although I’m having issues with your video. 
 

They don’t cause any issues and for me they went away on their own. I kinda miss them 🥲

 

They eat some of the smaller animals in the tank like baby daphnia, cyclops, rhabdocoela, etc.

[AllFishNoBrakes]

I’ve had Hydra 3 times, and they’re always in low to no flow tanks. 
1. Shrimp tank. Killed it with flubendazole. 
2. Single pair Kribensis tank. Killed it with flubendazole  

3. I currently have it in my Walstad 6 gallon cube. Leaving it be, for now. Haven’t seen any adverse effects. Looking to source a pair of Sparkling Gourami’s to see if they’ll naturally eat it. 
 

Early on in my hobby I was scared of it and heard it would kill shrimp and fry. At this point I’m more curious as to what happens if I just leave it while I source a natural predator that will eat it 

[Chick-In-Of-TheSea]

On 9/27/2022 at 1:24 PM, Biotope Biologist said:

I’m having issues with your video. 

If you click on the words You Tube in the video window it should take you to the vid on the You Tube site where it should play ok.

 

On 9/27/2022 at 1:23 PM, DiscusLover said:

Maybe small adult fish

I have this little pipsqueak black neon in that tank. He was recovering from bullying and columnaris.  I wonder if he will be OK with the hydra.

Now I'm getting curious.  This tank also has limpets.  Do limpets eat hydra or do hydra eat limpets?  I kinda think the limpet population is dwindling.  Hmm....

(in the lower right corner of the video you can see a big limpet)

[Biotope Biologist]

On 9/27/2022 at 10:42 AM, Chick-In-Of-TheSea said:

I have this little pipsqueak black neon in that tank. He was recovering from bullying and columnaris.  I wonder if he will be OK with the hydra.

Now I'm getting curious.  This tank also has limpets.  Do limpets eat hydra or do hydra eat limpets?  I kinda think the limpet population is dwindling.  Hmm....

(in the lower right corner of the video you can see a big limpet)

I had fry and baby snails in with my very robust hydra population and the hydra never touched them. 
 

Hydra do have stinging tentacles but if the snails can figure out how to attack them they make quite delicious snacks.

I wouldn’t worry too much about them

[TOtrees]

No-planaria works, but it's hell on snails. 

I've had hydra in many tanks at one time or another. I used to fuss about it, but not any more. I've never lost a baby fish or baby shrimp to hydra, that I know of. They usually explode when I'm feeding live bbs daily, to tanks that don't have enough consumers to eat it all really fast. They are not hard to get rid of by starving them out, eg feed a larger or sinking food that doesn't break up into tiny bits/dust in the water column. Frozen foods are ideal for this, like bloodworms and (adult) brine shrimp. 

I'm curious that the hydra in your video are so green. I believe this means they are consuming algae, but it would have to be suspended algae, like green water type. But your tank seems pretty clear. If this is a type of hydra that is able to utilize the products of living algae inside them photosynthesizing, starving them out might be difficult, and (barring chemical treatment) you might need to also cut the light levels. 

[Chick-In-Of-TheSea]

Here’s a shot of the whole tank. Couple of snails and the black neon that has been recovering. @TOtrees

Right now there seems to be a constant layer of plant matter that settles on the bottom. Just little bits that come off of the anacharis. I do vac that during water changes. Sponge filters are not clogged.

Edited September 27, 2022 by Chick-In-Of-TheSea

[Biotope Biologist]

On 9/27/2022 at 11:12 AM, TOtrees said:

 

I'm curious that the hydra in your video are so green. I believe this means they are consuming algae, but it would have to be suspended algae, like green water type. But your tank seems pretty clear. If this is a type of hydra that is able to utilize the products of living algae inside them photosynthesizing, starving them out might be difficult, and (barring chemical treatment) you might need to also cut the light levels. 

Hydra consume up to a 1/3 of their diet as FFA (free floating algae), they are not picky eaters but are a majority predatory.

[Katherine]

On 9/27/2022 at 1:12 PM, TOtrees said:

I'm curious that the hydra in your video are so green. I believe this means they are consuming algae, but it would have to be suspended algae, like green water type. But your tank seems pretty clear.

When I had them they were just as green as chick's and no green water. They were living on an algae covered decoration though.

[Colu]

I would just leave them a lone reduce feeding of frozen or live foods such as brine shrimp or daphnia that will significantly reduce there population for a week or two

[Chick-In-Of-TheSea]

On 9/27/2022 at 3:08 PM, Katherine said:

When I had them they were just as green as chick's

I think they’ve been here awhile and I’ve been mistaking them for hair algae.

On 9/27/2022 at 1:15 PM, Katherine said:

one or more of my nerite snails removed 98% of the algae and I haven't seen a hydra since.

I love excuses to buy more snails 😍

[TOtrees]

On 9/27/2022 at 3:08 PM, Katherine said:

When I had them they were just as green as chick's and no green water. They were living on an algae covered decoration though.

I'm willing to be proven wrong here, but I don't believe hydra are capable of 'grazing' off a substrate. They can only trap and consume food via their tentacles, from the water column. I did a bit of digging (and am therefore an expert 🤓) and some species of hydra can sustain symbiotic algae populations within their bodies ("can" not "must"). So the algae inside the hydra in Chick-in's tank could well be existing as individual populations within each hydra*, and not reflect food consumed from the water column as I initially thought. [Experiment: remove some of the hydra to a very dark tank and see if they lose (most of) their green color. ]

*Kind of like aquariums inside the aquarium. Which my brain finds intriguing and satisfying. 

[Katherine]

On 9/27/2022 at 2:47 PM, TOtrees said:

I'm willing to be proven wrong here, but I don't believe hydra are capable of 'grazing' off a substrate. They can only trap and consume food via their tentacles, from the water column

I suppose it's possible that they were eating free floating algae that wasn't concentrated enough for us to see it. Idk. 🤷

 

On 9/27/2022 at 2:47 PM, TOtrees said:

So the algae inside the hydra in Chick-in's tank could well be existing as individual populations within each hydra*, and not reflect food consumed from the water column as I initially thought.

That would be very cool! Kind of like upside down jellyfish.

[Guppysnail]

I did not read all the responses so this may all have been mentioned. 
 
I keep 3 kinds of hydra. I enjoy them. They eat small bacteria, protozoan and microfauna. Yes they eat the bad ones. If it’s small and living it’s fair game.

My shrimp tank often doubles as a fry tank for CPD ultra tiny hatching. I see no decrease in my numbers. I also see no harm to my shrimp. Maybe a new hatch one here or there but not enough to stop or noticeably slow production. Most of my tanks have them. I leave them. If there was no need for them they would not thrive. Currently my Scarlet badis tank that only eats live food has a thriving boisterous population. My panda Cory and the SB do not seem to notice. Neither do the snails and shrimp in that tank. 
 

No planaria has been reported to harm and even kill snails. 
 

PS my candy swirls snails are for hydra in the badis tank just to keep balance. And because I’ve always wanted an excuse to get them 🤣They are coming from Florida your home state 😁

Edited September 27, 2022 by Guppysnail

[Katherine]

https://en.wikipedia.org/wiki/Hydra_viridissima

Here's what Wikipedia has to say about green hydra. Sooo cool! And it makes sense that they were on my algae covered decor since that's also the best place for them to 'grow' the algae inside them.