Pix & ID: Critters that come in your rocks: the good and the bad.

[Flashy Fins]

I have these on a rock from another person's tank, which I don't think are bad, but I'm wondering if they have spread to another rock in the tank, or if I have a lookalike pest?

The tiny polyp in the top right area of the pics looks just like the polyps in my first picture. However, the polyp in the bottom left corner of these pictures seems different; there is no green on it, just brown. Also, the stem doesn't seem quite the same. It's not as darkly colored and extends out from the rock a little further. Not the greatest pics, but a better look at the stem:

Anything to worry about?

 

[alexander_ktn]

Spotted this dark colored thing in my tank; seems nearly black in reality, but showed up brown in the pictures. It was still for a while, but as I turned lights off and back on a couple times in an attempt to get decent pictures, he started moving. Speed was comparable to a snail. Starfish missing legs, maybe? Good or bad?

Thanks for your input! Learning a lot from this thread, although it's taking me some time to get all the way through it.

That's an Asterina starfish.

I have these on a rock from another person's tank, which I don't think are bad, but I'm wondering if they have spread to another rock in the tank, or if I have a lookalike pest?

The tiny polyp in the top right area of the pics looks just like the polyps in my first picture. However, the polyp in the bottom left corner of these pictures seems different; there is no green on it, just brown. Also, the stem doesn't seem quite the same. It's not as darkly colored and extends out from the rock a little further. Not the greatest pics, but a better look at the stem:

Anything to worry about?

A Protopalythoa species - please read up on them because they are poisonous and thus dangerous if handled incorrectly.

 

[Flashy Fins]

That's an Asterina starfish.

A Protopalythoa species - please read up on them because they are poisonous and thus dangerous if handled incorrectly.

Wow, I feel silly now! I've seen white asterina stars on my glass and knew what they were, thanks to this thread. Never occurred to me they aren't white on the other side. :spin1: I spotted a white one this morning and made the effort to check out his other side and surprise - it was the exact same starfish I took the pictures of! :lmao:

Thank you for the polyp info. I read up a bit and decided I don't want them in my tank (or should I say, taking over my tank), so I gloved up and took a hammer to a large rock to knock the bigger colony off. A smaller rock with new polyps, I just removed completely. Put all of it in my QT tank, where there is no light. If it survives, fine with me. Just don't want it in the display!

 

[taylorking2000]

Hi guys,

I've been cycling my tank for three weeks and just found this crab this morning. Can anyone tell me what it is? Looking to keep SPS soon so don't want this crab giving them any trouble.

Thanks!

Tried to remove it with tweezers but it's hole is too deep.

 

[OKDOHK]

taylorking2000, you will need better photos for a id. But it does appear to be a crab from the Xanthidae family. Most reefers would remove the crab. Have you thought of trying the weighted bait and jar method. If you catch him take some more photos for a proper id.

 

[caustin]

Alright. So I made the mistake of adding a couple corals without dipping them. Now I feel like a moron because I noticed a bunch of what appears to be eggs on the shell. I'm thinking that they're vermetid snails, but I'd like somebody to confirm that. It just looks like the red piece is actually part of the coral.

 

[worm5406]

From having some, YES that is a vermetid snail (the red tube). Can you pull it out?

I see some small dusters on there too. (good for them)

 

[caustin]

From having some, YES that is a vermetid snail (the red tube). Can you pull it out?

I see some small dusters on there too. (good for them)

I imagine I could find a way to pull it off the frogspawn. But I'm sure which ones are dusters and what are snail eggs. I'm still very new to this.

 

[Rob in Puyallup]

The vermetid snail doesn't seem to be bothering anyone for the time being.

As for tube worms, there are quite a few. The larger ones attached to the rocks, with lots of smaller ones growing on the tank itself. They seem to be competing against the coralline algae for space.

 

[caustin]

The vermetid snail doesn't seem to be bothering anyone for the time being.

As for tube worms, there are quite a few. The larger ones attached to the rocks, with lots of smaller ones growing on the tank itself. They seem to be competing against the coralline algae for space.

The tank is actually dirty glass. I did a water change today, spilled a little and left water spots. And there are several very large ones on the rocks, which I haven't made up my mind on what to do with yet since they came with the tank. Should I start removing all of them from my tank because I could have sworn they were thought to be beneficial?

 

[worm5406]

The curly ones are ok to leave.

 

[SushiGirl]

The white spirals are featherdusters, featherdusters are harmless. Vermetids are also harmless but can annoy both you & some corals. Not sure dipping would've done anything for a vermetid. Still good practice to dip, otherwise you'll end up with red planaria flatworms. You certainly don't want those.

 

[caustin]

Well, thank you guys. I appreciate the ID and the help with featherdusters. I have a couple of those throughout the tank, which if they're harmless I'll probably leave. I'll see what I can do for this vermetid snail so it doesn't annoy the frogspawn. I'll start dipping anything new I get and then I just need to get rid of what I believe is the last true fire worm.

 

[Flashy Fins]

Collinista snail? It looks like it to me, but I'm new at this and like having confirmation.

I spotted my first bristle worm last night! It was quite exciting.

Also spotted several amphipods. I recognized them right away, thanks to this thread, but I was not expecting the somersaults! I found them rather amusing. :spin1:

 

[Rob in Puyallup]

Is this a good critter for my reef tank? I have several that came attached to a small live rock. They're quite the wonderers. Measure about a half inch across.

 

[SushiGirl]

Flashy, that is a Collonista.
Rob, looks like a majano, not good. Run a search on ways to kill them before they take over.

 

[Rob in Puyallup]

Thanks for Sushi. It's a shame something this attractive can be a nasty.

 

[Rob in Puyallup]

PS: These majanos remind me of the critters that covered many live rocks back in the 80s. But I guess those could have been ricordias.

 

[GAAshley]

Great information thank you

 

[Rob in Puyallup]

Hi all,

I was just adding a bit of food to my tank a few minutes ago. While standing there I saw an odd, flat bell shaped critter zoom across the tank from front to back. It probably measures about an eighth of an inch long, a bit less in width. When it landed at disappeared in some of the coralline algae.

Sorry no pictures of this guy. Hoping someone around here might think of something from my vague description.