Is it possible that my banded serpent starfish ate my urchin?

[MikeCRK]

Is it possible that my banded serpent urchin ate my tuxedo urchin?

All was absolutely fine until the moment when urchin decided to hide in the cave where serpent starfish has their casa.

Starfish are opportunists but... is it possible?

 

[blaxsun]

Is the urchin dead or just hiding? I mean, if the urchin died I can see the serpent not passing up a free meal... I have 5-6 of the suckers in my tank and they've never harmed any of my urchins.

 

[MikeCRK]

Is the urchin dead or just hiding? I mean, if the urchin died I can see the serpent not passing up a free meal... I have 5-6 of the suckers in my tank and they've never harmed any of my urchins.

dead and hollow. I was hoping it is just "resting" but after three days hen I took it out - dead.

Trying to figure what happened, nothing has changed in the tank, everything else in it is thriving.
So here is a mystery...

 

[blaxsun]

dead and hollow. I was hoping it is just "resting" but after three days hen I took it out - dead.

Trying to figure what happened, nothing has changed in the tank, everything else in it is thriving.
So here is a mystery...

I've had umpteen urchins craw under rocks and die. Not sure if they got trapped there or what the deal was.

 

[Fishy888]

Urchins are sensitive to even small parameter changes. What are your parameters looking like?

 

[MikeCRK]

pH: 8.4 (it is middle of the night)
ALK: 6.5 (down from 7 last week)
AMM: 0
NO2: 0
NO3: 20
salinity: 1025

edit:
if it helps (but I doubt)
PO4: 0.5 (always like that)
Ca: 460

 

[Fishy888]

The drop in ALK might be at fault. Also ALK should be 7 to 12 dKh. There could be other issues in play here though as well.

 

[vetteguy53081]

Is it possible that my banded serpent urchin ate my tuxedo urchin?

All was absolutely fine until the moment when urchin decided to hide in the cave where serpent starfish has their casa.

Starfish are opportunists but... is it possible?

I would find that hard to believe but look first at water - something likely changed weather it be phosphate, temperature, salinity, calcium as examples and even starvation

 

[MikeCRK]

The drop in ALK might be at fault. Also ALK should be 7 to 12 dKh. There could be other issues in play here though as well.

Marine Pro is 7, never had any issues with ALK moving up down by 0.5.

 

[MikeCRK]

I've had umpteen urchins craw under rocks and die. Not sure if they got trapped there or what the deal was.

Nah, I was thinking same at start, but the urchin was having a lot of space to get in and out. Well, I think I was just unlucky with this one. First few days it was grazing like crazy, all over the place etc. Then got into the cave (the "you know who's cave" ) and that was it.

Thanks for the comments! I am setting up dosing pump to today to battle ALK.

and to add on the ALK topic. So urchin by some of you would die, but acros and other SPS are thriving, no other invertebrates are affected. No issue with plagues, newly introduced gorgonias are shooting polyps like mad:

I keep spectrum of animals in my tank, I do it deliberately as some of them (like above red finger) are my indicators if anything goes wrong depends on what could be the factor different animals would react. Good oldschool method. Like keeping clams in water treatment plants.

 

[blaxsun]

Nah, I was thinking same at start, but the urchin was having a lot of space to get in and out. Well, I think I was just unlucky with this one. First few days it was grazing like crazy, all over the place etc. Then got into the cave (the "you know who's cave" ) and that was it.

Sometimes the urchins aren't doing well and they just die. The fact that it happened in a cave out of sight is possibly just a coincidence. I know none of my "creepy crawlies" have ever even looked at a snail (let alone an urchin) sideways.

 

[MikeCRK]

Sometimes the urchins aren't doing well and they just die. The fact that it happened in a cave out of sight is possibly just a coincidence. I know none of my "creepy crawlies" have ever even looked at a snail (let alone an urchin) sideways.

yeah, I would need to stick to this scenario I like my little kraken (serpent) and let me believe it had nothing to do with urchin's death


A new urchin is arriving tomorrow. This time not blue tuxedo but red one. We will see how it will go this time, I also took cork worm (feather/duster) I find them really good as the water quality monitoring tools.

Strange enough today I have hundreds of baby copepods all over the tank The lamps just started.