Tank Tuesday: Interrupted by Wandering Starfish

Those who read last week’s Tank Tuesday post tuned in this morning to hear more about Ceti and Ghillie, the small seahorses I brought in to keep Cygnus company.

As the title indicates, that post is temporarily delayed on account of wandering starfish.

I went in to feed the tank this morning and saw this (and yes, I know the videos are larger than the text box – the subject is small and it makes him easier to see) :

The little guy with all the arms is a micro brittle star, a miniature echinoderm (class Ophiuroidea) related to the starfish you might have seen at the beach or in a public aquarium. Brittle stars come in a variety of sizes, from giant specimens that live deep in the sea to these little guys who frequently enter home reefs as “hitchhikers” hiding in live rock (and no, that’s not actually why the rocks are considered ‘live’).

My tank plays host to several dozen micro brittles (yes, literally), descendants of two micro brittlestars that hitchhiked in on a coral frag about 6 months ago. Most of the time, they hide in the rock or under corals where they can’t be seen (or eaten) by passing fish. When I feed the tank, they extend their little arms to snag pieces of mysis or frozen brine – since they’ve grown so numerous, feedings sometimes look like a cruise ship launch, with ticker-tape food floating through the air and a crowd of brittle-star well-wishers waving goodbye.

Brittle stars usually change their hiding places at night (when you’re essentially a snack food, it’s better to stay under cover when it’s light). Once in a while, a star goes “walkabouts” just before I turn on the lights. This morning was the first time I caught one on the glass.

For those who may be concerned about the little guy’s safety – he wasted no time finding shelter, as you can see in part 2: