What is this yellow thing?

I had one in my tank and it died (they have a short life span) I even have hitchhiker purple sponges for it to eat)...oh and it didn't nuke my tank(29 gal) which had 2 o. clowns a blue damsel, yellow tailed black blenny and a nem at the time.

 

its a yellow sponge

 

That is one beautiful nudi! it looks healthy for the time being! If it dies it will most likely nuke the tank, and sponges for it to eat will be difficult to come across. Keep your parameters as close to perfect as possible (get those nitrates down!!!) with out stressing the nudi. I would be a good idea to restrain from fish and such if you do plan on keeping it. I can't decide if that yellow spiral is a sponge or eggs. Beautiful creatures...nudis.... Good luck!

 

OK, here goes...it is one of the species being lumped under the name Hypselodoris bullocki. It eats only one or a possibly a couple of species of tropical sponges, none of which are available as food. Once they are collected, their starvation begins, and if they are well fed and healthy when they are collected, they will only live around three months before they finally starve to death. The yellow spongy thing is its egg ribbon. They lay eggs as a stress response, often just before they die. They are beautiful, but impossible to care for in aquaria.

Chromodorids, including this one, won't nuke your tank when they die, and the eggs won't hurt anything either. The ones that are dangerous to keep are the phyllidiid nudibranchs, which are colorful, slow moving, and don't have the external gill on the dorsum.

I don't recommend buying these since they are typically only going to live a month or two in your tank, at best, and buying them only encourages the suppliers to keep importing something that can't be sustained in reef tanks. That said, you may as well just enjoy it since you already have it, since it probably won't live much longer.

You can look the species up on the seaslugforum for more info:

The Sea Slug Forum - Hypselodoris bullocki

Cheers,



Don