Strange things at night

[ISpeakForTheSeas]

I’ve found a string with little tentacles on my zoas but also very little black dots running fast on them as well.

Not sure on the black dots (probably a pod of some variety, but microscope pics would be needed to say for sure). For the string though:

Those are Digitate Hydroids (definitely a Zancleid hydroid [taxonomic family Zancleidae], possibly a Zanclea sp.) - there's evidence to suggest that they're actually beneficial to the corals they grow on;* I don't know if they'd sting fish that get too close or not, but it is a risk - similarly, they may spread and cause issues by growing too numerous in the tank and possibly posing a risk to other tank inhabitants.

I know @Reefkeepers Archive had a colony of these - I don't know if they've caused any problems for them or not, but if they still have the colony, they'd have ~5 months of experience with them to relate.

*Source:

https://www.researchgate.net/publication/321938186_Corals_hosting_symbiotic_hydrozoans_are_less_susceptible_to_predation_and_disease

 

[blecki]

It looks like the same feeding tentacle I see occasionally. I always thought it was some kind of tube worm - lets out a long string with a 'spikey ball' at the end. Utterly harmless, at least in that I've had them growing in zoas for ten years and the zoas are still there.

Op, V was asking about the snails because they look like sundial snails, which eat zoanthids. Collonistas can also have that pattern but given that the snails are on zoanthids...

 

[Reefkeepers Archive]

Not sure on the black dots (probably a pod of some variety, but microscope pics would be needed to say for sure). For the string though:

Those are Digitate Hydroids (definitely a Zancleid hydroid [taxonomic family Zancleidae], possibly a Zanclea sp.) - there's evidence to suggest that they're actually beneficial to the corals they grow on;* I don't know if they'd sting fish that get too close or not, but it is a risk - similarly, they may spread and cause issues by growing too numerous in the tank and possibly posing a risk to other tank inhabitants.

I know @Reefkeepers Archive had a colony of these - I don't know if they've caused any problems for them or not, but if they still have the colony, they'd have ~5 months of experience with them to relate.

*Source:

https://www.researchgate.net/publication/321938186_Corals_hosting_symbiotic_hydrozoans_are_less_susceptible_to_predation_and_disease

Yep, at least that one is a digitate hydroid. I don't know about their effect on zoas but is their base growing out of the coral itself or the rock around it? The ones i have were growing out of my pectinia, they were there for quite some time but now they seem to be decreasing/have decreased in numbers. Are the zoas closed up around the hydroid? If so than it may be irritating it but otherwise it should be good. The only "negative" effect is that the coral doesn't like to grow/branch where the hydroid is but there are small on a large coral so it isn't too big of a problem.

 

[vetteguy53081]

So after some research today I am relatively confident that the tan looking critter from last night is indeed a stomatella . As for the black one, after researching that, I am starting to think Vetteguy may be correct. It could easily be either an elephant slug or a black stomatella, so I will leave it alone for now. But I do love thinking the other is almost certainly a stomatella.

That was my guess as they are active at night and slowly fade in the morning and hide well until lights ramp down or go off

 

[Reefkeepers Archive]

Yep, at least that one is a digitate hydroid. I don't know about their effect on zoas but is their base growing out of the coral itself or the rock around it? The ones i have were growing out of my pectinia, they were there for quite some time but now they seem to be decreasing/have decreased in numbers. Are the zoas closed up around the hydroid? If so than it may be irritating it but otherwise it should be good. The only "negative" effect is that the coral doesn't like to grow/branch where the hydroid is but there are small on a large coral so it isn't too big of a problem.

Also here are some photos of them as well as the deformed branch that some are growing on, may be hard to see against the green coral but there there

 

[Sophie"s mom]

That string either hydroids or tube from a vermetid snail or spinoid worm

Hello, I have a completely unrelated question for you. I hear you are quite the tang guy on here. I purchased some calurpa, both palm, and grape that I want to put in my display tank. So my question is will my Naso tang eat any of it? I am fine if he does, I just don't know if they eat that or not, and was hoping you might have some insight on this.

 

[vetteguy53081]

Hello, I have a completely unrelated question for you. I hear you are quite the tang guy on here. I purchased some calurpa, both palm, and grape that I want to put in my display tank. So my question is will my Naso tang eat any of it? I am fine if he does, I just don't know if they eat that or not, and was hoping you might have some insight on this.

Call it what I call it - Salad !!! Yes it will eat it

 

[Sophie"s mom]

Call it what I call it - Salad !!! Yes it will eat it

Excellent! That is the main reason I got it, I just thought it would also be a help in the department of CO2 removal while it is there, but If my Naso will munch on it, all the better. Thank you.

 

[Cthulukelele]

So after some research today I am relatively confident that the tan looking critter from last night is indeed a stomatella . As for the black one, after researching that, I am starting to think Vetteguy may be correct. It could easily be either an elephant slug or a black stomatella, so I will leave it alone for now. But I do love thinking the other is almost certainly a stomatella.

Both are beneficial, and if it's an elephant slug it's more or less the best possible algae eating CUC you can have. If actually an elephant slug, they're long lived and voracious algae eaters. A local reefer would probably give you $100+ for one haha. The only reason you never see them is they're horrific shippers who you only ever really get as a hitchhiker.

 

[Sophie"s mom]

Both are beneficial, and if it's an elephant slug it's more or less the best possible algae eating CUC you can have. If actually an elephant slug, they're long lived and voracious algae eaters. A local reefer would probably give you $100+ for one haha. The only reason you never see them is they're horrific shippers who you only ever really get as a hitchhiker.

In looking at images available online, I feel like that is what it is moreso than a black stomatella.

 

[Sophie"s mom]

Call it what I call it - Salad !!! Yes it will eat it

Okay I got a couple better pictures of the mystery critter tonight. I feel almost certain now that this is a black elephant slug, ! What are your thoughts?

 

[vetteguy53081]

Okay I got a couple better pictures of the mystery critter tonight. I feel almost certain now that this is a black elephant slug, ! What are your thoughts?

Yep, stomatella. Great occupant and algae eater

 

[WalkerLovesTheOcean]

Okay I got a couple better pictures of the mystery critter tonight. I feel almost certain now that this is a black elephant slug, ! What are your thoughts?

Glad it's not that flatworm! Now you have a great addition to your CUC!

 

[Sophie"s mom]

Glad it's not that flatworm! Now you have a great addition to your CUC!

Agreed I was pleasantly surprised to see it very out and about tonight. And glad to have trusted confirmation that this is a good guy not a bad guy

Yep, stomatella. Great occupant and algae eater

awesome and thank you for your help! Not knowing much about odd inhabitants, and some potential bad guys, it is nice to have confirmation this is a good guy! Thank you again

 

[ISpeakForTheSeas]

Okay I got a couple better pictures of the mystery critter tonight. I feel almost certain now that this is a black elephant slug, ! What are your thoughts?

Yeah, that's definitely an Elephant Slug (Scutus sp.) - you can see the shell under the mantle clearly in your pics.

 

[Sophie"s mom]

Yeah, that's definitely an Elephant Slug (Scutus sp.) - you can see the shell under the mantle clearly in your pics.

Thank you

 

[vetteguy53081]

Okay I got a couple better pictures of the mystery critter tonight. I feel almost certain now that this is a black elephant slug, ! What are your thoughts?

Elephant slug as a distinct white line on them

Stomatella"

 

[ISpeakForTheSeas]

Elephant slug as a distinct white line on them

Stomatella"

The white line is their shell peaking out from beneath the mantle, and it's not always visible - for examples:

The Sea Slug Forum - Scutus in aquarium

www.seaslugforum.net

Scutus breviculus - Wikipedia

en.wikipedia.org

Scutus sp. 1 Marshall Islands

www.underwaterkwaj.com

 

[Miguel.PT]

Not sure on the black dots (probably a pod of some variety, but microscope pics would be needed to say for sure). For the string though:

Those are Digitate Hydroids (definitely a Zancleid hydroid [taxonomic family Zancleidae], possibly a Zanclea sp.) - there's evidence to suggest that they're actually beneficial to the corals they grow on;* I don't know if they'd sting fish that get too close or not, but it is a risk - similarly, they may spread and cause issues by growing too numerous in the tank and possibly posing a risk to other tank inhabitants.

I know @Reefkeepers Archive had a colony of these - I don't know if they've caused any problems for them or not, but if they still have the colony, they'd have ~5 months of experience with them to relate.

*Source:

https://www.researchgate.net/publication/321938186_Corals_hosting_symbiotic_hydrozoans_are_less_susceptible_to_predation_and_disease

Thanks for your help! It’s definitely what I see on my tank! Just checked on a zoa colony and nowhere else. I’ll try to keep them under check. Cheers!

 

[Sophie"s mom]

The white line is their shell peaking out from beneath the mantle, and it's not always visible - for examples:

The Sea Slug Forum - Scutus in aquarium

www.seaslugforum.net

Scutus breviculus - Wikipedia

en.wikipedia.org

Scutus sp. 1 Marshall Islands

www.underwaterkwaj.com

So I can now absolutely confirm that my mystery critter s are indeed black elephant slugs. I saw the white line in the middle of one of them last night, as well their antenna are very short/ stubby. I also have at least 3 ! Could they become a problem in my tank? I know they are good CUC, but I can’t believe I have at least 3. So should I leave them be?