Sea Hares and the Endless Caulerpa War...

Sk8r

Staff member
RC Mod
Foster/Smith swore that the dwarf sea hare eats caulerpa. I've battled this stuff ever since set-up a move ago. It survived rock cooking that killed everything but caulerpa roots and one aiptasia.

I finally decided to bite the bullet and give this critter a try. It's quite personable, cute, moves fast---will eat absolutely any OTHER algae before it tackles caulerpa. They're sold at about 2-3", but can reach 1' in size, and I have a 54g tank.

They also 'ink' like an octopus if annoyed, and can destroy your tank so doing, so consider carefully: they like temps under 80 degrees, around 79, and meticulous water conditions: 1.024-6 salinity; 8.3-9.3 alk, 400-420 calcium, 1200-1300 mg. If you remotely consider getting one, be sure 1) you can maintain those conditions 2) you have shielded any powerhead it can get into 3) you have carbon and enough salt on hand in case of an inking 4) you have no aggressive fish that are going to pick on it.

If you can meet all these conditions, you may find this critter helpful: the jury is still out, but it is eating caulerpa. Whether it can survive on this diet, I don't know, but I am going to supplement it in hopes.

It is a tougher little slug than you might think. I have moved it by hand, and it has wandered nose-first into a torch coral and sat upon bristleworms, so it does not self-destruct. It is into EVERYTHING, so be prepared. It is light, does not shove rock, and will try every stupid move at least 3 times before it desists (talk about hard-wiring!) I confess I was a little squeamish about hosting a slug---I live in Washington, where slugs are epic---but this one is a hoot, and not at all objectionable to handle if you use exam gloves.
 
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I have a Dolabella Sea Hare. (The things I learn from the Sea Slug forum :lol: ) I've had it for around 3 months now, and this is what I've observed so far.

My tank temp is always at least 82 with a mid day high range of 84. As of yet, I've never noticed any sensitivity to the temperature.

Although I do keep my tank salinity at 1.025 - 1.026, on one occasion, the top off water was turned off and the tank reached 1.029 salinity with no impact on the sea hare (although this was not a prolonged time period at that salinity).

My alk was at 6.4 when I first added him to the tank. It's been up to 12.2, and I've never noticed a change in behavior at either of those extremes.

The lowest my calcium ever gets is 440, and usually it hovers at about 500. Again, he doesn't seem to notice or care from what I can tell.

I've seen the sea hare fall off of a rock and reached my hand in to move something inches from his nose, and he has never inked. From what I have read before, they need something in their diet in order to continue inking, and chances are by the time it reaches your aquarium, it will have exhausted its supply of ink.

They are definitely bulldozers of the aquarium world. I find out the hard way if there is anything coral in my tank that isn't well secured. Also, if you have sensitive corals, a sea hare could be a problem. Although it won't eat any coral, it will crawl directly over them as though they aren't there.

Mine seems to be nocturnal. I originally thought it was at the back of the rock when I couldn't find it during the day, but it actually buries itself under the sand.

Shielding a powerhead is definitely a must. Mine will climb onto a powerhead at least twice a week to eat the algae on it.

They are actually a bit picky about what type of algae they will eat. I've never seen mine get near red turf algae, but hair algae was completely eradicated from my tank in a matter of a weekend. If he can get to a rock, he will eat the algae on it. I have one rock that overhangs the others, and although I've seen him hang upside down on other rocks, I've never seen him attempt to get on top of the rock that overhangs.

When you run out of algae as a food source, try nori. Mine loves it. Since he can scale the walls of the tank, I just use a clip on the glass.

I'm not sure how similar the dwarf sea hare is as far as sensitivity and eating habits, but I've been very happy with my Dolabella sea hare.

(Oh, and just to prove me wrong, he is now on the rock that overhangs for the first time since I've had him. :p )
 
I have been battling caulerpa for over a year now. I finally broke down & bought a tuxedo urchin. I have had him for almost 2 weeks & he is thinning it out nicely. I decided I really like him & as long as he eats green stuff I won't gripe if he eats the purple. I'll just have to get more corals to cover the rock.:rollface:
 
My tangs crush the stuff. If I ever run out of nori I just grab a handfull out of the fuge and put it in the food clip. It never lasts very long.
 
The dwarf seahare is apparently diurnal: he's up there in mh lighting getting suntans. He eats in one spot, rushes on to the next at blinding speed---for a slug. He can orbit the entire 54g tank in an hour, stopping to eat along the way. He doesn't bother my corals---he shies off from lps and doesn't crawl on them: he's had one set-to with the clam, but after getting his head shut in a clam twice in one minute decided against that. He rides the Sea Swirl nozzles: they're now clean. And he doesn't dislodge the more precarious of my corals or rocks. No problems. The 'stickiest' portion of his body seems to be his tail: he often adheres with only the last half inch of his body, while stretching out into the water to explore, possibly smelling the current: they are said to have quite a sense of smell, and will find food. I think mine is confused by the smell of algae coming in from the fuge---and he can never finid it.

Another caulerpa eater is the gratillis urchin (Foster/Smith), but they grow like mad. I started with a golf ball and 6 months later ended up with a softball that was nudging my larger rocks, so he went to a much bigger tank. The bigger they get, the less they can get into crevices.

So far the sea hare is doing a decent job. You pull out what you can and let him get the rest.

If your tank is under 75 g a tang is not a good option, unfortunately. Neither is a rabbitfish---especially since they often go after lps if grazing gets scarce: in the limited confines of a 54, they get bored waaaay early....
 
Manual removal and a bunch of emerald crabs did it for me. I haven't had that for 5 years now. Too bad that now I have something worse, this red hair algae that's like steel. I do have a foxface in there that eats it and it never touches any corals. As long as you keep them fed they are a great fish to have IMO. First I tries a doliatus, but it would rather eat fish food. Swapped it for a small unimaculatus and it eats algae constantly.
 
Glad to know re the foxface. I tried a scribbled, and it was a pita. THanks. My little guy is still munching, which gives me hope.
 
Re: Sea Hares and the Endless Caulerpa War...

<a href=showthread.php?s=&postid=14289788#post14289788 target=_blank>Originally posted</a> by Sk8r
They also 'ink' like an octopus if annoyed, and can destroy your tank so doing, so consider carefully

Sk8r, you (and everyone else out there) don't have to worry about the sea hare inking and killing your tank. The ink has been proven to not be toxic, simply distracting. Word doesn't spread fast about things being safe, though. Most likely any tankmate deaths noticed by reef keepers that coincided w/ sea hare deaths were because of poor water quality due to decomposition of the sea hare. Hope that you continue to enjoy your sea hare, and that all your pump intakes are covered.
 
I have a foxface that loves caulerpa and he never messes with my corals. He is a very hardy fish. I have tried sea hares but have a hard time keeping them alive for very long.
 
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