The only thing that I found after a lot of research is that it belongs to family Dasyatidae. But I would like to have the genus and species. Please help! Thanks!
Well it doesn't work like that, does it?
Someone can only tell you what your fish is if they know the answer. And that is still the case whether you help one person with their question or a hundred. Also, you posted your question only 4 days ago so you may have to wait a bit. I finally got an answer to one of my questions recently after waiting six months.
Also, in my experience, the forum is best at answering questions about British wildlife, followed by questions from further afield in Europe, Questions that are from different continents are least likely to find someone who knows the answer.
I suggest you hang on in there for a bit and see what happens.
Welcome to the forum and thanks for all the contributions you made in such a short time. Unfortunately, we don't have enough experts to cover all domains, and we don't have an NHM fish expert contributing to the Forum. In many cases, none of us knows the ID of this or that specimen posted here, so we just hope one of the members will reply. I feel bad when I see those enquiries that go unanswered for months, but I can't help - I simply don't have the expertise to answer all of them. Whenever I think I can help with an ID, even with just an opinion, I do that. Many times I make mistakes, but I'm happy to learn from other members. I hope someone will see your photo and will answer your question.
Thanks to both for the replies - I just believed that the identifiers of this forum are mainly curators from British Natural History Museum, so they are specialist with wide knowlegde in their study areas, including exotic species (and foreign species forms the majority of material of the museum, at least on display, and almost always well identified).
So I see that the level is lower, but even then I'm surprised that not only this ray, but none other of the topics that I've posted here, is replied.
I appreciate your frustration Isidro, but as Alan and Florin say, there are very few professional taxonomists on the forum and many of us amateurs do our best to help point people in the right direction...possibly...hopefully!
It is also my experience that if you post something for identification that is completely unknown to you you are more likely to get a reponse. Indicating that you know family, genera etc does seem to make it less likely that someone will reply with a helpful answer. Or you may have to wait months for someone like yourself to come along and answer many in one fell swoop!
Your contribution is very welcome, please try to be patient, people will respond when they can make a helpful contribution...
I have looked at the internet and I think that this fish may be Gymnuria poecilura or long-tailed butterfly ray. This species has the spotted tail which your picture shows. The web site is www.noeyeddear.com/fish/shark-ray-catfish.html
As some of the previous members have said most of the forum members are amateurs with knowledge of specific areas., I am a retired fisheries scientist but my identification of world-wide species is not necessary encyclopaedic.
Another useful fishy site is www.fishbase.com