Hi Nor. From the picture I understand very bad, but the shape of the stoma and the presence of a hairy periostracum, you might be treated to a Tateidae (Truncatelloidea), close to Potamopyrgus. cordially

Hi Nor, the "Hair" mentioned here is the PERIOSTRACUM - a thin organic coating or "skin" which is the outermost layer of the shells of molluscs and brachiopods as clearly pointed out by Dr BINI! 

Jonathan, did you mean TEREBRALIA? 

Bini, yes, it looks close to Potamopyrgus..

Thanks Johanset and Bini. Next time I need to put more clear picture for the identification. Anyway, your answers are very helpful. 

Hi, Deepak, thanks for the information. After I refer to few references, I agree with Dr. Bini and you. I think it looks more close to Potamopyrgus sp. But, I have to re-check with mollusc expert in my country. Maybe they have encounter with this species before.

Thanks everyone!

Hi Jonathan. I found it on mangrove sediment. It's a brackish environment. But I wonder..do algae really looks like that? I preserve them in alcohol for a long time already. I think it is impossible that algae still attached on the shell.

We also find periostracum with fine hairs on some live species in south Florida.  This is definitely not a Truncatellidae.  The specimen appears to have spiral grooves or ridges, which I don't think of as being typical of Hydrobiidae.  Is it possible this is a Thiaridae?  

G. Lynn Wingard is absolutely right about the Hydrobiidae remark. It  is also large for Potamopyrgus. It looks like a thiarid. But thiarids are neither that small, hairy (although some are spiny) or smooth. It is an estuarine littorinid of India: Mainwaringia leithii.

I agree with Ümit: it is Mainwaringia leithii (E.A.Smith 1876), family Littorinidae. See description in: Reid DG 1986 Mainwaringia Nevill, 1885, a littorinid genus from Asiatic mangrove forests, and a case of protandrous hermaphroditism. Journal of Molluscan Studies, 52 (3): 225-242.

I agree with Gianluigi.

Hi Shankhadeep, this is definitely Mainwaringia leithii. Please check the reference before reaching an unfounded conclusion.