Hello,
Identifying halfbeaks is not easy. There are at least four species traded regularly, and the actual number is probably quite a bit higher. Basically any species of smaller halfbeak gets sold as a "wrestling halfbeak" and the larger halfbeaks as a "Celebes halfbeak".
The fish in your avatar are definitely "large" halfbeaks of the genus
Nomorhamphus. They are all pretty similar in terms of requirements, breeding, and so on. I've got some stuff up on my web pages that might interest you,
here and
here.
The two common species of
Nomorhamphus are
Nomorhamphus liemi liemi and
Nomorhamphus ebrardtii. Both are sold as Celebes halfbeaks, though only the first species "officially" has that name.
Nomorhamphus ebrardtii is sometimes called the red or orange fin halfbeak because it has red on its fins instead of red and blue. Note that colour is very variable, sometimes with mood. Breeding males usually have the strongest colours, but I've got breeding males with no colour at all, so it isn't a sure fire thing.
If you look over my pages, you'll see pictures of my halfbeaks and they might help you decide which species you have. Male
Nomorhamphus ebrardtii have long straight beaks without a downward curl, while
Nomorhamphus liemi liemi have short, curly beaks a bit like goatee-beards. Females of both species tend to have short, stubby beaks.
Halfbeaks are great fish, and since I've been keeping them I have found them to be lively, easy to tame, and fun to breed.
Cheers,
Neale