Donya's Slugarium

[Donya]

Thought I would get this slugarium business rolling finally...

Primary tank goal: house a large Dolabella auricularia sea hare that has proven to be much more toxic than is the norm for the species, wiping out all but one fish and almost all of my sea urchins in two different tanks as it was moved from one to the other. So, the big rules for this tank are: no fish and no sea urchins.

Secondary tank goal: an opportunity to house other normally fish-toxic animals. Sea hares don't live very long, and the one responsible for this tank being set up is already quite large, so it may already be about to enter old age or will do so in probably at most another 6 months. I will be adding other Aplysiids along the way, probably another D. auricularia or two since I am aware of some captive breeding successes with this species.

Tertiary tank goal: coral grow-out? Corals were unharmed by the primary subject for the tank.

Tank: 20gal high (US gallons)
Rock: ~12lbs as 3 pieces of LR
Substrate: ~1-1.5" of dry aragonite, soon to be deepened with a bag of live sand I picked up.

In-tank equipment
- Current: one powerhead (temporary to remove sand silt) with floss-covered intake, a heater (also temporary) and an air line
- Planned: no powerheads (for heat reasons in the summer), heater only in extreme low temps, air-only flow, and air-driven skimmer

Lighting
Current: one T8 bulb in a grow-light sort of fixture
Planned: hopefully a lot better as LEDs or something if I want to have anything to do with that third goal LOL


The tank got thrown together quite fast since I needed the sea hare moved into it. All rock is from cycled tanks so I'm seeing no cycle and some CUC is in already. Although it is invert-only and therefore less demanding on filtration than a tank with fish, I am monitoring daily to see how it handles things with relatively little rock.

I need to clean the glass, but...

The main subject acclimating:

A small slimey friend:

Part of the current CUC:

Current stock:
- 1x Dolabella auricularia
- 1x Dolabelifera...something. I forget right now. It's the one that looks like a flat toad.
- 6x Clibanarius striolatus*
- 2x Calcinus elegans

* The Clibanarius striolatus will NOT be part of the long-term CUC for this tank as they get quite large. After a couple of molts they will be moved. The species is hard to find and they are so small they don't have a safe home anywhere else. As they grow they will get moved with the other C. striolatus I have and only the Calcinus elegans will remain (I may need another couple - they serve as bristleworm control). C. elegans has been peaceful in all instances that I have had it with small Clibanarius species, so although I have introduced risk here by temporarily mixing species (and genera) it is a lower risk than others I have seen. Even so, it's split into the east side and west side hermits. They do not go on the same rocks.

Stock that will get added soon when the sand bed gets a bit better:
- 2x Strombus luhuanus conches

 

[lljdma06]

That is one gross looking slug. Ewwwwwwww!

Glad it's finding a home of its own where it can live out its final days in comfort.

I like my Calcinus elegans. A bit clumsy and prone to murderous acts on unsuspecting snails, but otherwise a delight.

Will be watching this with interest. I wonder what that slug will do when it finally dies.

L

 

[Donya]

I think I just found a hidden use for this tank: de-fuzzing things. My sun coral got hit by a fuzz bomb (the whole 'fuge in my 55gal turned into a fuzz bomb actually while I was being distracted by other nuked tanks) so I'm acclimating it and a small mushroom to this tank right now for cleanup.

Finally got a replacement wooden airstone for my skimmer so I can get that going again this weekend.

I wonder what that slug will do when it finally dies.

Probably nothing interesting. You can tell you're on their way about a week beforehand, sometimes longer if you're keeping a really close watch since you can see the slow down in appetite and activity. A day or two beforehand its really obvious and I usually isolate them that point both for the purpose of not having them harassed and to not have a tank inked (this happens in death sometimes as the body stiffens).

 

[Donya]

Finally re-found the name of the flat toad sea hare: Dolabrifera brazieri. Native to Australia. According to an archived thread on the sea slug forum with photo evidence, if you tick them off, they secrete foggy stuff from glands whose functions are not understood.

Totally gonna go for a cucumber in the stock list. However, I'm not sure whether I want to go for a sand mopping species or one of the filter feeders (in which case my skimmer needs to take a hike...got other places I can put it I suppose). I have managed to keep mad crazy populations of filter feeders in other tiny tanks so the food prospects aren't really the worry for me, but that group seems less explored/documented with the exception of sea apples and their atrocious captive record (in fact, I haven't even seen any for sale since moving to New England!). Perhaps the filter feeders are all more-or-less like the sea apple in that regard and that's why the lack of info...hmmm. There is a small yellow filter feeding species that I occasionally hear about reproducing in captivity but I'm never sure if that's legit or not since nobody ever shows photos. Time for more reading.

 

[lljdma06]

Finally re-found the name of the flat toad sea hare: Dolabrifera brazieri. Native to Australia. According to an archived thread on the sea slug forum with photo evidence, if you tick them off, they secrete foggy stuff from glands whose functions are not understood.

Ewwwwwwww!

Totally gonna go for a cucumber in the stock list. However, I'm not sure whether I want to go for a sand mopping species or one of the filter feeders (in which case my skimmer needs to take a hike...got other places I can put it I suppose). I have managed to keep mad crazy populations of filter feeders in other tiny tanks so the food prospects aren't really the worry for me, but that group seems less explored/documented with the exception of sea apples and their atrocious captive record (in fact, I haven't even seen any for sale since moving to New England!). Perhaps the filter feeders are all more-or-less like the sea apple in that regard and that's why the lack of info...hmmm. There is a small yellow filter feeding species that I occasionally hear about reproducing in captivity but I'm never sure if that's legit or not since nobody ever shows photos. Time for more reading.

Donya, actually John Maloney from reef cleaners is hooking me up with a very small yellow filter-feeding species for my 8g biocube. I wanted an interesting CUC and he gave me an interesting one, that's for sure. He says, and I trust him as being a good authority, that they are quite hardy and easy to care for. When I did my reading up on them, I also saw that they breed in the aquarium. This may be the species you're referring to? He didn't mind one for me as I have an all-in-one and there as minimal risk of one getting sucked up.

Colochirus robustus? This is being sold at liveaquaria.

 

[Donya]

Donya, actually John Maloney from reef cleaners is hooking me up with a very small yellow filter-feeding species for my 8g biocube. I wanted an interesting CUC and he gave me an interesting one, that's for sure. He says, and I trust him as being a good authority, that they are quite hardy and easy to care for. When I did my reading up on them, I also saw that they breed in the aquarium. This may be the species you're referring to? He didn't mind one for me as I have an all-in-one and there as minimal risk of one getting sucked up.

Colochirus robustus? This is being sold at liveaquaria.

That sounds like the right one. While I have aggravatingly not been able to find a source giving as much detail as I would like, the one book I have with fairly detailed cucumber info still has Colochirus robusts listed as still being toxic to fish. Hobby suspicions seem to be that they're just less likely to respond aggressively than some other species.

 

[lljdma06]

Donya, actually John Maloney from reef cleaners is hooking me up with a very small yellow filter-feeding species for my 8g biocube. I wanted an interesting CUC and he gave me an interesting one, that's for sure. He says, and I trust him as being a good authority, that they are quite hardy and easy to care for. When I did my reading up on them, I also saw that they breed in the aquarium. This may be the species you're referring to? He didn't mind one for me as I have an all-in-one and there as minimal risk of one getting sucked up.

Colochirus robustus? This is being sold at liveaquaria.

That sounds like the right one. While I have aggravatingly not been able to find a source giving as much detail as I would like, the one book I have with fairly detailed cucumber info still has Colochirus robusts listed as still being toxic to fish. Hobby suspicions seem to be that they're just less likely to respond aggressively than some other species.

Like I said, I trust John, if he says it's cool, it is. It's one of those where I think a bad incident or two have defined a species. I remember you and I had a similar discussion way back about pencil urchins, yet Mr. Spinypants ended up being a very peaceful, fragile member of my biotope. Not the predator that Schemeck makes them out to be.

I've read a few threads that shared experiences with these cucumber, it's been mostly positive. The negative experiences were due to a lack of feeding. They're filter feeds, you gotta feed them. It's like not feeding porcelain crabs. They also give you a good warning before they die by beginning to shrink.

L

 

[lljdma06]

What do you know about the freckled sea hare? I'm not interested in one, but I dunno, would you perhaps be?

L

 

[BigTom]

Nice! Sea hares are really cool, here's a shot of a UK native species (photographed in the Channel Islands)

 

[Donya]

What do you know about the freckled sea hare?

No idea - I've never heard this common name. Sea hares are a bunch where common names tend to be pretty uninformative unfortunately, save for a few famous ones (e.g. the California sea hare). I would probably need a pic to know which species it is.

Is it by chance a blue-spotted species? If so, it may be Bursatella leachii, a tropical species that sometimes shows up.

I'm not interested in one, but I dunno, would you perhaps be?

Possibly! The main risk with mystery sea hares is that many species are coldwater, which is of course the make or break thing for this tank since it already has animals with lower-end tropical requirements and not having a chiller rules out strictly coldwater species for me in general (although it's something I want to do eventually). If you transplant a coldwater sea hare into a tropical environment, they burn out incredibly fast, so there is no middle ground. Coldwater species are relatively rare in the trade but do show up every so often, sometimes being mistaken for more tropical counterparts.

Like I said, I trust John, if he says it's cool, it is. It's one of those where I think a bad incident or two have defined a species. I remember you and I had a similar discussion way back about pencil urchins, yet Mr. Spinypants ended up being a very peaceful, fragile member of my biotope. Not the predator that Schemeck makes them out to be.

I've read a few threads that shared experiences with these cucumber, it's been mostly positive. The negative experiences were due to a lack of feeding. They're filter feeds, you gotta feed them. It's like not feeding porcelain crabs. They also give you a good warning before they die by beginning to shrink.

The two cases still feel rather different to me. One is a statement that is bizarre even by the standards of other information available on the genus and the other is basically what I have seen with my black sea hare: animals belonging to groups that are well-known for their toxicity need to be handled with care. Up to my tank nukes I fell into the so-called black swan trap with my assumptions on the sea hares. There were so overwhelmingly many good cases that I was quite convinced that Dolabella auricularia must be safe, despite the info on general toxicity of the animals. And it seems I was wrong! If nothing else, that business taught me a lesson: if there are toxins in an animal, they can probably get out of the animal one way or another. The issue is then whether or not there is an effect.

With cucumbers, just as for sea hares, it makes sense that they could be kept safely a vast majority of the time in a well-prepared tank, including Holothuria species known for their fish-toxic Holothurins. It's not the toxic animal itself that's the issue, but rather whether something else in the tank will be able to make it angry/threatened enough to commit one of the famously catastrophic responses (such as expelling organs as a last ditch effort when they think they're about to be eaten). It's hard to anticipate whether a situation like that can/will arise in a given tank unless it's a sort of padded cell species tank. For example, I imagine those rotten worms that I'm pretty sure set off my sea hare could set off a cucumber. Even so, a toxic response may go without effect if the animal is small, the water volume is quite large, and/or the chemical filtration & skimming is very aggressive. Different animals can also exhibit different levels of susceptibility to the same type and amount of a toxin.

Not that any of this has stopped me. I am already having detritus problems in this tank. Back when this tank had fish and other things in addition to the sea hare I couldn't understand why there was so much crud. Seems to be down to the amount of undigested stuff that passes through the sea hare (which is not the case for the little toad-slug; that species seems more efficient). And so...this little sand mopping dude is giving me a hand and also enjoys mushy, falling-apart carnivore pellets that the hermits don't get to fast enough.

If I see the detritus running low (or a sudden absence of cucumber turds), I can add more mucky pellets and other foods in front of it...or I can just feed the sea hare some more.

Nice! Sea hares are really cool, here's a shot of a UK native species (photographed in the Channel Islands)

Cool! An Aplysia species I presume?