Bubble shells

Wow old thread.

 

"Bubble Shells" actually refers to opisthobranchs, a relatively recent development in the snail world (Stomatellas belong to one of the most primitive groups). The "bubbles" generally mean Bulla, Bullina, Hydatina, and a few related genera, most of which do indeed feed on tiny worms. You can find specifics on their feeding on the Sea Slug Forum.

Cheers,



Don

 

Does anyone here have (or have had) Bulla Occidentalis? It looks really cute. Is it really a micralgae grazer? Is that slime on the video I posted from the slugs, or is it plant matter? (I wouldn't want them mucking up a reef...)

Also, I found this on the sea slug forum:
http://www.seaslugforum.net/hamicymb.htm
This is like the prettiest slug EVER. Anyone keep them? According to Wikipedia, they secrete chemicals to keep carnivorous fish away, I wonder if it's toxic enough to cause a problem in a closed loop such as a reef tank... If not, this could be a prime candidate for keeping as an algae eater...
I mean look at this, it's beautiful!

 

Yes, I've kept Bulla occidentalis. They aren't very impressive residents, since they usually only come out at night, and tend to look like snot balls covered with grains of sand when they do. They're harmless, though. Most reef tanks don't really have the right conditions to keep them long term, since their natural habitat is mucky sand with a layer of microalgae and organic detritus.

I've also kept Haminoea cymbalum and Haminoea ovalis, and attempted to keep Haminoea antillarum. You find the first two in filamentous green algae growing on dead coral heads, at night, and the latter I've usually found in pools with a muddy sand substrate and some microalgae (sometimes with macroalgae as well). They all tend to hide during the day time, and although H. cymbalum reportedly grows over an inch long, the majority of them are less than half that size, with the shell only being around a quarter of an inch long. They are very photogenic, but not all that impressive when you are trying to spot them visually. My experience has been that they tend to just disappear in a tank, but I don't know if they starve, if fish eat them, or if they die of old age. Many opisthobranchs have very short life spans in any case, and these are probably no exception.

Cheers,



Don

 

Hey, thanks for the reply. So they are more on the shy side.
Did you see any extensive grazing behavior from them at night? What is their approximate lifespan? And have you ever heard of breeding in captivity?

 

I never really saw any evidence of their feeding, like, they never made a trail through the algae. Three to six months is typical of the lifespans of many of these snails, although I don't know how much variation you'd see between these species (probably not much between snails in the same genus, but the heavier-shelled Bulla species probably live longer, maybe a couple of years). The Bullina species only showed up in Samoa two or three months out of the year, then died off. I'm not sure how they managed to reappear every February...Hydatina was also seasonal. Never heard of anyone breeding them in captivity.


Don

 

Here's a note on lifespans from the Sea Slug Forum:

"Like most aspects of sea slug biology, there is no general rule concerning their life history and life span.

Most species seem to live for about one year, although the tropical Sea Hare Dolabella auricularia can live for six years in an aquarium and the Antarctic cephalaspidean Philine gibba can live for up to four and a half years in nature. On the other hand there are small nudibranchs, especially those that live and feed on short-lived cnidarian colonies which have extremely short life cycles. For example both the European aeolid Tenellia pallida and the coral-eating tropical aeolid Cuthona poritophages can mature in three weeks, and probably die within two or three months. In the case of these very short-lived species, they need to complete their life-cycle before the colony they live and feed on dies. If they are too slow then they will themselves die from starvation before they can breed.

It is also important to realise that many sea slugs have a free-swimming larval stage so that the offspring can escape from their parent's dying colony and find a new one of their own."

The free-swimming stage is what makes raising them in captivity difficult.

Cheers,



Don

 

Hey,

Thanks for all the info. I see you're an absolute snail expert. Is there an active, cool-looking algae grazer you'd suggest for a nano tank?

 

There are some awesome looking Turbo species that are fairly hard to kill and are great algae grazers. Some are even fairly small, like Turbo castanea. They come in a variety of colors and patterns, and average less than an inch, although they may grow twice that large eventually. I see them for sale fairly often. Turbo petholatus and T. reevei are also pretty, and good grazers, but average a little larger. They aren't quite as hardy as T. castanea. If they are encrusted when you get them, you can take a pocket knife and wire brush to the shell to reveal the natural colors. It won't hurt the snail. Turbo petholatus and T. reevei are almost never encrusted though.

Turbo (Marmarostoma) castanea
Turbo (Turbo) petholatus
Turbo (Turbo) reevii

 

Ah...so those orange snails from the Caribbean are probably T. castanea then. I never knew the species name for them. Too bad we can't polish our snails...pretty pic.