Dear Paresh,

It seems like an ascidium to me. However, I think the best form for making photographs of animals like this is putting them on water, so their real morphology will be apparent.

Hope this helps.

 Thanks Fernando.

yes, Ascidiacea . Don't forget to mention size when you need identification !

regards RG

Thanks Romain.

It looks like solitary ascidian and it may belongs to Corella eumyota or some other Corella sp. and for further details use http://www.ascidians.com/, it will be  helpful

This is a pelagic Thaliacean of the genus Salpa. The white string inside the animal is a stolon plenty of developing Salpas. The orange 'nucelus' is the stomach + the intestine of the animal.

Thanks to all.

Probably under Ascidia.

This is definitely a pelagic tunicate Thaliacea not Ascidiacea

Thank you Vladimir Sir.