I don't think thats a Nudi. It's a sea cucumber. Look at its attatching feet, they go all around its body Nudis have a snail/slug like foot and often tassels, this little guy is useing what should be tassels as atttching devices like an urchin or sea cucumber.
i had some bad experiences with them,they get sucked into the powerheads and messes up your entire tank
Your decision, really..but Dean, my reply may help YOUR DECISION...a bit, I hope! If the relative amount of dendritic tentacles (external branch-growths) are many..then most likely a PRIMARY PLANKTIVORE! It looks like you have one here... ....You said it was with your ROCK Decide if system maturity,and biodiversity/refugia yields are enough to healthily sustain the animal's plankton food source. ~ Will it outstrip reproductive rate of refugia plankton species, hence starve, and DIE? ~ Reduced plankton is UNDESIRABLE, BUT WORSE is DEATH OF ANY HOLOTHURID(sea cucumber) in our relatively small environments... many toxic complications from poison emission, or stress-induced evisceration( turning insides out, yeeuucchh!!!) Also, if it proves to be a PRIMARY DETRITIVORE...which this shows few anatomical signs of, are you intending to keep it intank, where you DON'T WANT any debris? Or, maybe, if you were considering the Holothurid as a refugium inhabitant....consider it's feed requirement rate VS your "waste" production rate AS IT'S FEED SOURCE. ie, ~ will you have enough DIRT/DEBRIS/DETRITUS for it as an efficient sand-sifter? ~Do you even WANT your substrate to be sifted? ALL Holothurids produce varying levels of toxins, so should only ever be restricted to maitenance of relatively small species. Weigh up the benefit-loss scale. Some are shy and withdraw tentacles, at slight disturbances...missing meals, and starving to death...dangerous!!! Here's another caution... "It is vital that sea cucumbers only be associated with peaceful unmolesting fishes and invertebrates." [Baensch Marine Atlas 3] by Dr Robert Patzner HTH
Yip, pretty sure I will have plenty of that for it to eat Just kidding, thanks for the awesome reply, I will keep it in my live rock cooking tank for the meantime. Do you think I could release it into our waters or rather not?
Well, Dean where is your rock from? ..I mean dealer/country of origin, if you know.. Best is donate it BACK (ie, return) Or give to someone with a large , ESTABLISHED sandbed, or multiple refugia setup....ensure they have knowledge of it's requirements and downside/s too! Thanks for caring....enough.
My rock is from all over, Kenya, Indonesia, some 2nd hand rock from other peoples tanks, so no idea where this little critter came from. Anyway, thanks for the help, much appreciated.