Anyone have any idea what's crawling around on my glass?

[hoffmeyerz]

So I did a water change two weeks ago and a few hours after I was done I noticed a spot on the glass. I thought I just missed a spot but a little while later I noticed it was in a different place on the glass....hmmm....missed spots don't move! When I took a close look it I could see it was something alive and moving around on the glass. Looking real close I swore I saw what looked like a pair of tiny tentacles sometimes, like a snail. I found one other one as I looked more.
Today I'm finding a few more and am very curious what they might be. I haven't had any snails in the tank for many months now. I'd love some insight if anyone might know what these are.

 

[HankstankXXL750]

Does it have a shell? Could be a limpet. If so no worries for the most part. If no shell could be a flat worm. If so could be an issue depending on type. Here is a webpage that I use to identify hitchhikers.

Reef Tank Hitchhiker ID · Saltwateraquarist.com

Some reef tank hitchhikers are good, while others are bad or neither. Here is a reef tank hitchhiker ID list for the most common hitchhikers.

saltwateraquarist.com

 

[JTP424]

Do you have snails in your clean up crew? I forget what type but I always thought these were baby snails.

 

[ISpeakForTheSeas]

Yeah, that looks like a limpet to me (they actually are snails, just with flatter shells). Good CUC.

 

[hoffmeyerz]

I had three snails when I moved moved my stock over to this tank a year ago. The tank never went through the ugly stage and unfortunately I don't think it developed enough food for them and I lost them a few months in. The tank has still stayed pretty clean of algae and only a little diatoms now and then so I've been afraid to put more snails in and watch them starve.
I just saw one in my overflow which made it easier to get a pic of the back of it. It does look like a limpet from the link Hank posted above. I don't know anything about them, don't seem to be causing any issue but I am seeing more and more of them.

 

[HankstankXXL750]

I had three snails when I moved moved my stock over to this tank a year ago. The tank never went through the ugly stage and unfortunately I don't think it developed enough food for them and I lost them a few months in. The tank has still stayed pretty clean of algae and only a little diatoms now and then so I've been afraid to put more snails in and watch them starve.
I just saw one in my overflow which made it easier to get a pic of the back of it. It does look like a limpet from the link Hank posted above. I don't know anything about them, don't seem to be causing any issue but I am seeing more and more of them.

I have them in my tanks and don’t know if any issues. The article did say some eat corals, but I’ve never heard anyone say they are a problem. They will eat algae.
Yes my lfs advised against getting too many snails as they could starve especially in a new tank.

Don’t really need them if not having algae problems, but if you start to get some they can really keep your tank clean.

 

[ISpeakForTheSeas]

I have them in my tanks and don’t know if any issues. The article did say some eat corals, but I’ve never heard anyone say they are a problem. They will eat algae.
Yes my lfs advised against getting too many snails as they could starve especially in a new tank.

Don’t really need them if not having algae problems, but if you start to get some they can really keep your tank clean.

With regards to them eating corals:

Normal limpets are totally fine, but there's some speculation about Keyhole Limpets possibly eating SPS corals. If yours is a keyhole limpet (which it looks like it may be, but the photo is too grainy for me to tell you for certain), I don't know that anyone has actually confirmed that they eat SPS (much like how people believe "Asterinas" - actually Aquilonstra - stars might eat their corals: it might be a species specific thing, it might be a you have way too many starfish so they're out of other food options thing, it might be they're eating the slime coat/mucus on the coral rather than the coral itself, or they might just opportunistically eat unhealthy corals).

If it has a little "keyhole" or bullet hole looking hole on the back of it's shell (where the shell comes to a point) then it's a keyhole limpet.

Personally, I'd assume keyhole limpets are probably safe, but I know a lot of people would rather play it completely safe and not take the risk.

 

[hoffmeyerz]

Thank you for the replies! I was just a little surprised since they seem to have come out of nowhere and I had no idea what they were. I'm assuming they're like the pineapple sponges that showed up and control their own population based on their food supply right?

 

[sfin52]

I had three snails when I moved moved my stock over to this tank a year ago. The tank never went through the ugly stage and unfortunately I don't think it developed enough food for them and I lost them a few months in. The tank has still stayed pretty clean of algae and only a little diatoms now and then so I've been afraid to put more snails in and watch them starve.
I just saw one in my overflow which made it easier to get a pic of the back of it. It does look like a limpet from the link Hank posted above. I don't know anything about them, don't seem to be causing any issue but I am seeing more and more of them.

Limpets eat film algea. They are good guys.

 

[hoffmeyerz]

Thanks sfin!

 

[HankstankXXL750]

Thank you for the replies! I was just a little surprised since they seem to have come out of nowhere and I had no idea what they were. I'm assuming they're like the pineapple sponges that showed up and control their own population based on their food supply right?

Basically. I haven’t seen them overrun any of my tanks.

 

[alonsooro]

Good fauna. That's part of tank biodiversity and yes, if you have all in check their population will too. I can't see a lot of your tank but I assume you're still cycling or in a young reef. If you have tons of them it means maybe something is not balanced so you can look for a natural predator, I think a yellow coris can do it. But only do it after observing and knowing that you have a problem with that. Right now doesn't seem like a problem. Good luck

 

[hoffmeyerz]

Tank is 75gal and is a year old, not cycling. Parameters stay pretty steady with the exception of an Alk drop lately that I need to figure out and address.
Sal- 1.025
NO3- 15
PO4- .09
ALK- 5.5
I don't have any corals and it's a long story but right now I only have a pair of clowns in there and a pajama cardinal in qt healing its fins from a bully clown! I need to add more fish, hoping to do that soon!!
I'm not sure what brought out the limpets, I'll just watch them for now.

 

[HankstankXXL750]

My tanks have been running for over a year and I discover new things. Some probably been around, others maybe brought in with new corals. I have now started QT corals to try to avoid this.

 

[HBtank]

Limpet, good guy and haven’t really seen people have issues with them (like crazy numbers).