brittle star behavior

Nov 27, 2002
Not sure where to place this rather non-octo query, so I’ll try here.

I do some pretty regular maintenance of my tank, including plucking algae off my live rock, scouring the glass clean, feeding the corals, and dropping in some food pellets for my echinoderms (a few brittle stars and such.) Naturally my timid octo, Gollum, crawls even deeper into his den when I do this! In doing this routine, I have discovered a rather strange of my brittle stars, a red serpent star, has learned to identify the scent of my hand and associate it with food. At first, when working in the tank he would remain hidden, and only come out for pellets that I’d scatter after I was done. Now, just seconds after my hand hits the water, he is aggressively out and moving towards it! And at that point, I haven’t even handled food yet.

I took invertebrate zoology and covered echinoderms, but I really don’t remember enough. I was under the impression that these guys lack or almost lack a central nervous system. Do they (apparently) have enough of a CNS to make an association like this?

A large red brittle star i have had learned to always been in contact with the octopus as that was wher it got its food from. it just seemed to patiently wait until the octo had finished and got the scraps.

During the day the brittle star would always have at least one arm touching the octopus!
Re: brittle star behavior

rrtanton said:
Now, just seconds after my hand hits the water, he is aggressively out and moving towards it! And at that point, I haven’t even handled food yet.

I wonder if this demonstrates the principle of Pavlov's Brittlestars?

(Sorry to be silly).

Although I have no brittlestars, I have observed similar behaviors in some of my other fish. I had a scat ( since passed on) who shared a tank with my stonefish, Charybdis, who is a monster and tried to eat the scat on the first day of his arrival. After that incident, the scat would herd the feeder fish and ghost shrimp towords the cave in which Charybdis spends most of his time, without ever trying to eat him themself. The logical conclusion is that if Charybdis was well fed, he would no longer try to munch on the scat ( who was too big for him to swallow that first time, and was spat out after I poked Charybdis with a chopstick) Smart fish or what?
Then, in a different tank, my puffer fish, Uter, will immediately swim to the top of the tank to get his brine shrimp after I turn on The Daily Buzz in the morning. The TV is half way across the room, but must give off enough light or sound to clue him in.
Finally, Amiga, the Betta I have in a bowl on my desk at the office, always starts flailing about when I gather up my keys from the desk to go home for the day. I don't know if he is aware of the time, the motion or the sound, but without fail he protests my departure as only a fish can. He must be a lonely fish at night!
Love the names!!! My executive director has a tank, I helped set up in his office with a parrot cichlid. His assistant swears this fish knows her, and waits for her every morning!

I really believe fish learn to reconize their "food source" as well as other mammels do! My department thinks I'm nuts!!! OH WELL!!!!!

I believe it...after all, if a brittle star can "learn" to associate my scent with food, then I have to think fish, with decent brains, can do a bit more than that.


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