A Biological Experiment?

Yes, it is.

The whole thing is.

I consider the tank my own personal BioLab.  I am keening interested in the processes of cause and effect in relation to our 75 gallon saltwater tank.  That is why the main page of this blog publishes different aspects of readings along with the days actions so that changes in those readings may be directly correlated to actions of the past.

Why the scientific slant for a lead up?

Because yesterday, my wife and I observed a new form of life in the tank:

It was a creamy white and about 3/4's of an inch in length.  It's a ground-based life form, so no swimming.  We first noticed it moving toward an opening in one of the rocks we have toward the front of the tank.  It was wandering in and out of the rock and occasionally onto the substrate.

At first, as it was moving away from us, it appeared to have a fuzzy head with a single leg extending from the rear.  I initially described it as a one legged jellyfish.  It then disappeared into the rock.

Moments later it became visible again as it exited the opening in the rock.  I could see what look like two appendages in front of the animal.  Those appendages ended with spheres.

With this new detail observed, it appears as though this animal is some sort of snail.  I didn't notice a shell at all.  Or at least the shell is the same creamy white as the animal itself.

While we scrambled to get the camera set to the macro setting in order to take a picture, we lost it.  I'll be keeping a close eye out for it today.  I'd like to get a picture of it.

So where does the "Biological Experiment" title come into play?

• I have not intentionally added any life forms except Damsels and Dwarf Hermit Crabs.
• It has been two or three weeks since anything new (15 lbs of live rock) was added to the tank.
• In the past week I've stopped using tap water for water changes and top-off's (mainly because I'm out of salt mix).  I've been using RO/DI water from the LFS.  In the past 4 days I've added 15 gallons (20%), and I think it's interesting to monitor nutrient levels since the switch.

I think it's amazing to see watch the effects of simple everyday causes that I introduce into the system, plus the contributions of the tank itself as it matures.  I suppose if I didn't, I probably shouldn't have a tank.

So here I am wondering what single cause would produce this effect of a new snail hitchhiker...  It's probably not a single cause, but the orchestra of multiple causes.

• The use of RO/DI instead of tap water causing an increase of the health of the tank
• The addition of live rock a couple weeks ago
• The addition of the Aqualite at the same time as the rock
• The addition of flow into the tank within the week

It's been two weeks since adding the live rock.  This snail was most definitely a hitchhiker on the rock.  I wonder in what form I received the snail...

Eggs?  If so, how many?  The snail is pretty small and due to it's color is really hard to notice on the white crushed coral substrate.  About a third of my live rock is white, also.  I may have more of them, but until they mature, they will be hard to see.

Immature hatch-lings?  Maybe.  This would account for so far seeing only one.  If it were eggs, I would think that I would notice more of them, especially near the hatching site (where ever that is).

Could the rock work I performed this week have somehow allowed this snail to become viable?  Or at least noticeable?  What about the removal of the Damsels?  Could they have been eating these critters?  Now without a possible "predator", perhaps "they" are now able to grow to a size that more noticeable.

And should I hold off on vacuuming substrate for a week or two in the hopes this snail becomes more visible so that I may avoid throwing it out with a water change?