Where were these images taken?

Photographs are not very good, so some identifications tentative:

1) Echidna nebulosa

2) Gymnothorax thyrsoideus

3) Pomacanthus semicirculatus

4) Halichoeres marginatus

5) Chrysiptera brownriggii

6) Pomacentrus proteus

7) Pomacentrus proteus

8) Neoglyphidodon bonang

9) Chrysiptera brownriggii

10) Ostorhinchus sp. (cookii or taeniophorus)

11) Istigobius ornatus

12) Blenniidae indet.

13) Bathygobius (?) coalitus

14) Halichoeres marginatus

15) Abudefduf vaigiensis

16) Siganus canaliculatus

17) Neopomacentrus sororius

18) Halichoeres marginatus

19) ? [fish not distinguishable on photograph]

Dear Melissa,

I have taken these photos from rocky coastal areas of Sri Lanka.

Dear Dr. Ronald,

Thanks a lot for the identifications. Yes I understood that the photos are not in good quality. Hence proper identifications are difficult. As such, I am grateful to you for your identifications.

Thanking you,

Gayashan

Hai

      ya sure, send the photos 

Hi Kannan,

Please find the attachment herewith. Thank you

Is this Pomacentrus trilineatus or Pomacentrus proteus?

This is Pomacentrus proteus. The species is common in Sri Lanka; it is only found in Sri Lanka and the eastern Andaman Sea. The lower half of the body in the juvenile is yellow; the adult is mostly bluish grey, including the caudal fin.

Pomacentrus trilineatus is restricted to the Western Indian Ocean (Red Sea, East Africa, Seychelles, Madagascar and Mascarenes); it has a pale caudal fin  and posterior dorsal and anal fin in adults, and a much more yellow body in juveniles. The two species are illustrated in Allen (1991):

Allen, G. R. 1991. Damselfishes of the World. Mergus Publishers, Melle, Germany. 1-271.

Dear Dr. Ronald,

Thanks a lot for the description. It is interesting P. proteus is only found in Sri Lanka and the Eastern Andaman Sea. I will read the description given by  Allen, 1991.

Thanking you again,

Gayashan

Dear Dr. Roland,

is this a single species or not?

Yes, these are very young specimens of P. proteus.

Dear Dr. Ronald,

Thank you very much for the answer.. Is it P. proteus or Neoglyphidodon boning ?

Best regards.

You are correct, this is rather Neoglyphidodon bonang, which has a single blue line on the head, and an additional small blue spot dorsally on the caudal peduncle.

Dear Dr. Ronald,

Thank you very much for the answer and the information given.

Besst regards