Jump to content

Profiles - Australian Native Snails


fishmosy

Recommended Posts

This thread is for posting profiles or experiences with Australian native snails. Please feel free to contribute with profiles or your experience with our amazing natives.

Edited by fishmosy
Link to comment
Share on other sites

Thiara amarula - Spiny Marsh Snail

(More pics soon)

snail3Johnson_zps2dabeb5d.jpg

The Spiny Marsh Snail is an Australian native that is rarely found in the trade. This is a shame as it has an interesting shell shape and is well suited to aquarium life, providing a few simple conditions are met.

The Spiny Marsh Snail was first described by Linneaus in 1758 as Helix amarula, with a subsequent remaining of the genus to Melania in 1822, and finally to Thiara in around 1943. It is found from the east coast of Africa, through Madagascar, north to the Philippines, through the Solomon and other Pacific Islands, and along the north-eastern coast of Australia (See Schutt & Glaubrecht, 1999 for a global distribution map). Given this widespread distribution, it is surprising that its distribution in Australia is limited. It is found from the Bloomfield River (south of Cooktown) to approximately 100km south of Cairns. Thus it is limited to around 6 major tributaries.

The Spiny Marsh Snail is found in the lower freshwater sections of rivers, generally just above the tidal range. It is probably tolerant to low levels of salt as it would be exposed to brackish conditions in drought years, and therefore may be suitable for brackish aquaria. This requires further investigation.

In its natural habitat, the Spiny Marsh Snail is found amongst rocks and pebbles, but also sandy areas, which is where I found them in the Johnstone River. In aquaria, they regularly bury themselves, especially when exposed to bright light. However in low light, or if the tank is densely planted or shaded, they are happy to move on top of the substrate and even climb the walls. This makes them useful for removing dead spots in substrates, but may mean they could dislodge plants in heavily planted aquaria, but I have not kept them under these conditions – something to watch for.

I have noticed they are particularly active at night and may graze algae from the glass during this time. I’ve seen no indication that it eats plants, and indeed plants are generally absent from its natural habitat, other than Vallisneria or Aponogetons. They happily eat prepared foods (shrimp/fish food) as well as some greens (cucumber/zucchini). However, they seem to spend most of their time grazing.

The Spiny Marsh Snail grows to a maximum size of approximately 50mm, perhaps slightly larger. From what I’ve seen, they are fairly slow growing and long lived. This makes them excellent candidates for aquaria, because unlike other pest snails, it makes it easier to control their numbers. Indeed breeding in aquaria is unlikely because it is thought the Spiny Marsh Snail releases planktonic larvae that move into the brackish/salty areas of rivers before migrating back up the river to settle. However, the true breeding habits of this snail are still unknown and present a challenge for aquarists. Nevertheless, these characteristics make it unlikely that the Spiny Marsh Snail would ever be a pest in aquaria.

One condition that seems to be an absolute must for this snail is that pH needs to be 6.5 or above. In acidic conditions (pH < 6.0), the shell dissolves and the snails refuse to come out of their shells. If your snails are not active, check your pH. That said, this doesn’t mean that they require lots of dissolved minerals (e.g. calcium carbonate). The TDS of the Johnson River where I found these was only 28 ppm at the time, so Spiny Marsh Snails may be the perfect tankmates for Neocaridina shrimp (cherries) and Australian native shrimp, but less so for Caridina (crystals, bees, ect.).

So if you are after a snail that is good looking, hardy, a good algae eater, turns over the substrate, easy to feed, won't bloom into a pest population, is native and presents a breeding challenge, I highly encourage you to track down some Spiny Marsh Snails. Why not try a biotope tank with Vallisneria or Aponogetons and Caridina gracilirostris?

Some additional material worth reading

Field trip to Johnson River, Queensland Australia with habitat description and pictures.

http://shrimpkeepersforum.com/forum/index.php/forum/62-field-trips/

Paper on reproductive structures of Thiara amarula - Australian specimens, by Schutt and Glaubrecht, 1999

http://www.naturkundemuseum-berlin.de/fileadmin/startseite/institution/mitarbeiter-publikationen/glaubrecht/Schütt___Glaubrecht_1999.pdf

Atlas of Living Australia – shows the collection points of Thiara amarula in Australia.

http://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:78fdb9ed-f4cb-4006-a78e-f394430ec676#

Edited by fishmosy
  • Like 1
Link to comment
Share on other sites

Nice one, how do they cope with pH closer to 7? I might have to find some for my tank. Promote this to the library if you don't mind sharing.

Link to comment
Share on other sites

pH 7.0 is fine. The water in the Johnson River was 7.0 when I was there, so no hassles. I had them at 5.5 and they weren't happy, at all. Their shell started dissolving and they wouldn't come out. I should've thought about it, but it didn't click until I moved them into a different tank and then they were all happy.

Also forgot to mention, they may not be available too often because you have to brave crocs to get to them!

I'll promote it once I get some better pics that really show them in all their splendor.

Edited by fishmosy
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Join Our Community!

    Register today, ask questions and share your shrimp and fish tank experiences with us!

  • Must Read SKF Articles

  • Posts

    • sdlTBfanUK
      Good to have an update and good to hear you are getting shrimplets, so hopefully your colony will continue and you may not get to the point where you have to cull some to stop over population. These type of shrimp only live 12 - 18 months so the adult deaths may be natural? If you have the time I would do weekly 25% water changes, adding the new water via a drip system and do some vacuuming clean of the substrate each week, even if only a different bit each week! See if that helps in a few months and if it does then stick with that regime? It should help reduce any build-ups that may be occuring!
    • beanbag
      Hello again, much belated update: The tank still has "cycles" of 1-2 month "good streaks" where everybody seems to be doing well, and then a bad streak where the short antenna problem shows up again, and a shrimp dies once every few days.  I am not sure what causes things to go bad, but usually over the course of a few days I will start to see more shrimp quietly standing on the HMF filter, and so I know something is wrong.  Since I am not "doing anything" besides the regular 1-2 week water changes, I just assume that something bad is building up.  Here's a list of things that I've tried that are supposed to be "can't hurt" but didn't prevent the problem either: Dose every other day with Shrimp Fit (very small dose, and the shrimp seem to like it) Sotching Oxydator Seachem Purigen to keep the nitrates lower Keeping the pH below 5.5 with peat Things that I don't do often, so could possibly "reset" the tank back to a good streak, are gravel vac and plant trim, so maybe time to try those again. One other problem I used to have was that sometimes a shrimp would suddenly stop eating with a full or partially full digestive tract that doesn't clear out, and then the shrimp will die within a few days.  I suspected it was one of the foods in my rotation - Shrimp Nature Infection, which contains a bunch of herbal plant things.  I've had this in my food rotation for a few years now and generally didn't seem to cause problems, but I removed it from the rotation anyway.  I don't have a lot of adult Golden Bees at this point so I can't really tell if it worked or not. Overall the tank is not too bad - during the good streaks occasionally a shrimp will get berried and hatch babies with a 33-50% survival rate.  So while there are fewer adults now, there are also a bunch of babies roaming around.  I guess this tank will stagger on, but I really do need to take the time to start up a new tank.  (or figure out the problem)
    • jayc
      If that is the offspring, then the parents are unlikely to be PRL. I tend to agree with you. There are very few PRLs in Australia. And any that claim to be needs to show proof. PRL genes have to start as PRL. CRS that breed true after x generations doesn't turn it into a PRL. Neither can a Taiwan bee shrimp turn into a PRL despite how ever many generations. I've never seen a PRL with that sort of red colour. I have on Red Wines and Red Shadows - Taiwan bee shrimps. So somewhere down the line one of your shrimp might have been mixed with Taiwan bees and is no longer PRL. It just tanks one shrimp to mess up the genes of a whole colony. 
    • sdlTBfanUK
      Sorry, missed this one somehow! The PRL look fantastic and the odd ones look part PRL and part Red wine/Red shadow in the colour. They are still very beautiful but ideally should be seperated to help keep the PRL clean if you can do that.  Nice clear photos!
    • GtWalker97
      Hi SKF!   So I bought some PRL (or at least they were sold as such. These claims are dubious in Australia as people don't know much about the genetics, nor do they care as long as they can make a quick buck). After 8 generations of breeding true, I'm having around 1 in 200 throw a much darker red. They almost look like Red Shadows, but I don't know too much about those types of hybrid. Can anyone help with ID'ing the gene?   TIA (First 2 pics are the weird throws, second photo is their siblings and the last photo is the parents)
×
×
  • Create New...