Cowries reef safe?

[Heavymman]

Did a quick Google search, apparently the gold ring and money cowrie are NOT the same. Although they look similar.

Gold Ring cowrie:
Monetaria annulus


Money cowrie:
Monetaria moneta

Mine looks more like the Monetaria annulus from the pictures I have googled. This is where and what I have, https://www.reefcleaners.org/aquarium-store/money-cowrie

Don’t forget the 3rd type of this species the Nomoremoney cowrie, commonly found with a reef tank full of coral ;Woot

 

[Heavymman]

This is what I found in another thread, hope it helps:

Expand below and credit goes to @tupes

I found this for you. Hope it helps.

If you search through the posts on Reef Central, you will find a lot of contradictory info. It all boils down to this (pretty much): for years, cowries were considered to be herbivorous grazers. Someone discovered that they are actually grazing off microorganisms most of the time rather than algae, and published that they were carnivores. A bunch of people took that "carnivore" word and ran with it, and assumed they ate everything from coral to other snails. Around the same time, people started collecting live Cypraeovula species from the cold waters of South Africa, and Zoila species from Australia, both of which feed on sponges. So now that these are widely known to eat sponges, people don't differentiate them from the common tropical cowries, most of which DON'T eat sponges, and you see quotes like "those eat sponges" even if the species were in different genera from the South African and Australian endemics. Also, with the age of the internet, some of the reefing experts (who are apparently a far cry from snail experts) started publishing photos of ovulids eating gorgonians and soft corals and calling them "cowries," which they are certainly not.

The TRUTH: cowries graze, and they have little ribbons of rasper teeth, and they may rasp at whatever they come across. They obviously don't all eat the same thing, or there wouldn't be a couple hundred species. Some are more specific than others in their dietary requirements, and the more widespread a species, and the more varied habitats in which it's found, the more likely it is to be a generalist feeder. Most of the species found in aquaria are these generalists, because the others will usually die too easily due to a lack of suitable food or water conditions.

Which species are usually kept?

Cypraea (Neobernaya) spadicea
http://www.gastropods.com/9/Shell_89.html
The Chestnut Cowry is a cold water species, caught off California or Baja, and sold because they are pretty and readily available. They won't last in a tropical reef tank, but make a pretty shell for your shelf after you keep them for a few weeks.

Cypraea tigris
http://www.gastropods.com/6/Shell_96.html
Often sold to aquarists, hardy, large, tend to be bulldozers in tanks, but normally don't eat anything objectionable. That said, your well-behaved Tiger Cowry may get hungry and go on a tasting spree, and over and over people report that their nice Tiger Cowry decided to mow down a whole patch of zoanthids overnight. I've never found this species associated with zoanthids in the wild, and I suspect that zoanthids are not a preferred food...but, large cowries eat a lot, and if it has eaten all the suitable food, it very well might start tasting of other things in your tank.

Cypraea (Mauritia) arabica
http://www.gastropods.com/7/Shell_37.html
A common generalist feeder, the Arabian Cowry is one of the easiest to keep alive. A friend kept one for over 20 years (long beyond the life expectancy on the reef) by feeding it wilted lettuce and clams on the half shell. They are fairly large, and if you don't feed them, will probably eat all the suitable "grazing" material in your tank in a short period of time. Once this happens, the same things that happen with hungry Tiger Cowries may start to happen: they will taste of all kinds of things in your tank that they might not otherwise bother.

Cypraea (Monetaria) caputserpentis
http://www.gastropods.com/4/Shell_44.html
The Snakehead Cowry is offered for sale occasionally, and I know of at least one that was kept for several months successfully, maybe longer than that. I'm not sure whether this species could thrive in a reef tank, since they aren't really live-reef animals. They live on the dead rocks in the most wave-pounded areas near the reef edge, and feed primarily by grazing the algae and microoganisms off the rocks at low tide, at night, ABOVE the water line. I don't know of any reports of this species experimenting by eating prized zoa's, so it may be a safer species to keep in a reef tank, assuming you can keep it alive. It would be almost impossible to duplicate the natural habitat for this species in a reef tank.

Cypraea (Monetaria) moneta and Cypraea (Monetaria) annulus
http://www.gastropods.com/6/Shell_76.html
http://www.gastropods.com/6/Shell_36.html
The Money Cowry and Gold Ringer Cowry are probably the most suitable species for a reef tank. These small cowries are closely related, and often interbreed on the reefs. They do seem to prefer slightly different habitats, but both species are widespread across the Indo-Pacific and may be found in a great variety of habitats. One or the other occasionally gets accused of embedding itself in a zoa patch and eating them. I can't say this doesn't happen, but I can say I've never seen it happen. They also get accused of tasting of other things, and since there is usually no photo of this actually happening, it's often guilt by proximity. My experience is that they will normally spend their time cruising the rocks and glass, eating the algae and microorganisms that they encounter, but they MIGHT taste of other things in your tank, especially if you have an extremely clean tank with no growth on the rocks or glass. As you mentioned, they have been observed grazing on cyano as well, but I don't know if this is "normal" or if the cowry just grazed through a patch of it. It's more typical to see them eating algae, and Charles Raabe posted a fairly detailed account of his Cypraea annulus eating hair algae last year on Dr. Shimek's forum at Marine Depot. I think all potential cowry-keepers should read it:

http://forum.marinedepot.com/Topic72161-11-1.aspx?

There are a few other cowries that turn up in reef tanks, but the above behaviors are fairly typical for all the ones an aquarist is likely to encounter. None of them normally eat corals and none of them prey on other macro life.

Large cowries are showy tank inhabitants, but you pretty much have to just figure that you will sacrifice whatever they bulldoze or smash or eat in order to have something that pretty in your tank. I'd personally sacrifice the occasional zoa colony to keep one, but not everyone feels the same way.

 

[norfolkgarden]

Our money cowrie is 6 years old. One of the few things in our tank that old. Never noticed it eating anything in particular. Hasn't done any damage I'm aware of.

Lol, $11 in 2012.

 

[Tastee]

My Cowries are Money Cowries.

 

[mort]

Money/gold rings are really useful and they can live far longer than your other cuc because they are pretty hard for hermits to eat. I'd say they are about as safe as cowries go and would recommend them to anyone. The larger cories can be problematic bulldozers but these little ones are great.

 

[McPuff]

Money/gold rings are really useful and they can live far longer than your other cuc because they are pretty hard for hermits to eat. I'd say they are about as safe as cowries go and would recommend them to anyone. The larger cories can be problematic bulldozers but these little ones are great.

I have always wanted a cowry and this thread has pretty much made up my mind. Gotta see if my LFS can get in this money cowry! Would 2 of them be too many in a 300?

 

[mort]

I have always wanted a cowry and this thread has pretty much made up my mind. Gotta see if my LFS can get in this money cowry! Would 2 of them be too many in a 300?

They are tiny, about 1" fully grown so you could have quite a few more than 2 if you have sufficient food.

 

[McPuff]

They are tiny, about 1" fully grown so you could have quite a few more than 2 if you have sufficient food.

Ok, excellent. Didn't know if they were really voracious. I know it's easy to overstock some CUC, such as sand sifting stars and emerald crabs. Thanks.

 

[Tuan’s Reef]

Well it’s been past 72 hours since what I guess is gold or money cowries been in my tank. All corals and inhabitants is safe and accounted for lol

There was a nice patch of long GHA near where my RBTA hangs out that is munched up by the cowry. Have plenty algae on my back wall I’m hoping they will clean up

 

[samnaz]

Money and gold ring cowries are reef safe IME.

 

[McPuff]

My LFS ordered 4 money cowries for me... they'll be ready for pick up in about 2 hours. How's that for service!!

 

[vetteguy53081]

Cowries are indeed. In the future: DO research prior to any purchase as you may acquire a specimen that is impossible to catch or remove from tank without taking everything you worked for Apart

 

[VA5]

Larger cowries also are prone to knock things over due to their size.

 

[CheckeredPants]

Snakehead cowrie are another reef safe variety. I’ve had mike for 2 years and it’s been a great member of my CUC.

 

[Tuan’s Reef]

Well ok!! I had patches of what look like bryopsis algae and now it’s gone! Not sure if the cowry or the cerith snails I added.

Found this guy on my back wall.. exactly where I was hoping it would go . Think they are staying if nothing goes wrong.

 

[McPuff]

Just added 8 money cowries to my reef this weekend. They are really cool looking.

 

[pjb9166]

Maybe someone who has kept them with soft coral can chime in. It seems like only problem I saw was with the tiger cowrie

Well now I know what kind of Cowrie my son picked up. We had two. Unfortunately one passed. We've had them in our mixed reef for a few months. All hammer, frog sp, zoas, anemones left unscathed. The only thing I see them/it do is graze. I do have a question I want to throw out there. Had anyone witness them lower themselves from, in our case rock work? It seems it hangs from a thread. Kind of like a spider does. I'll try to get a video of it next time.

 

[Tastee]

I have always wanted a cowry and this thread has pretty much made up my mind. Gotta see if my LFS can get in this money cowry! Would 2 of them be too many in a 300?

I have 4 in a 65g and they are doing well along with a couple of Trochus and a Nassarius (plus a Hermit crab) so you can definitely have a few in your 300. The Hermit and Nassarius are 18 months in my tank, Trochus 6-9 months and the Cowries have been there 2 1/2 months now.

 

[vetteguy53081]

They are fantastic herbivores, however are known to collectors of shells making then popular , not so much as CUC members. Many of the few cowries whose diets have been examined will feed on sponges, tunicates, or soft corals, while the diets of most species of wild cowries are not known.

 

[Airw0lf75]

I’ve been keeping Cowries in a Reef tank for about 10 years. I mean the exact same cowries. They’re all still alive. I keep 3 types, the money cowrie, gold ring, and snakehead. They all seem to only eat algae. In particular, they prefer Bryopsis. Otherwise, they hide all day and crawl around at night eating all the bryopsis. If you stick with those 3 types, you won’t have any issues. They don’t eat any of my sponges, soft coral, hard coral, they don’t even eat the snowflake polyps growing everywhere.