What happens when you let your saltwater tank evaporate off for a month or so, then do a water change?

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The punchline here is BABIES.  It turns out that some sea animals, in this case featherdusters, some kind of worm, and snails all like to reproduce when they are put under stress.  Specifically the salinity dropped from 40+ PPT (S.G. 1.032) to 28-30 PPT (S.G. 1.021), the temperature probably dropped as I added room temperature or colder water.  I also agitated the tank with a turkey baster to help the filter pick up snail waste and to dislodge some stubborn algae.

Anyways, here are some pictures of the creatures I noticed, including some nocturnal bristleworm looking things, and copeopods, which I missed in my last post about the denizens of the tank.

Baby snail!

These guys crop up with some regularity actually.  I suspect some of them dont make it, and others rapidly grow up.  Occasionally I see some that are just 1-2mm long, this one was about twice that size.

Just a blurry view of my aquarium…or is it?

At first glance, this is just a really bad photo of the aquarium where the AF decided to focus on the glass.  But when I looked closer…

Upon closer inspection, there is a baby tube worm/featherduster!

I noticed teeny tiny feelers coming out of this guy.  When I tapped the glass, he snapped back into his coil-thing, just like the featherduster!  I can only assume that they are related.  I can’t wait for these to grow up; there are a whole bunch of them sprinkled around the aquarium.

This appears to be a bifurcated bristleworm

This guy may not be a baby, but it certainly caught my attention with its weirdly bifurcated body.  It seems to be due to trauma and not genetic, because one side is much longer and the bifurcation did not seem to be symmetrical.

Last but not least, a copeopod

This guy (to the right of the pink thing in the middle) is a copeopod.  These are ALL OVER the tank, and they feed on pretty much anything.  They like to pester the featherdusters (the burrow/shell of which can be seen directly below the ‘pod).

Thats all for now.  Tomorrow I may go chiton hunting somewhere on the shore of mass, so there may be forthcoming posts about that!