The place you purchased the seahorses from should be able to tell you what species they are.
As for UV, that depends on who you ask because there are proponents and opponents for with or without.
I don't use them and never have in my 18+ yrs of reefing.
Uv is only going to get the pelagic stages of pathogens and algae and not even all of them at that, so you will always have pathogens present.
The key is to keep the tank very clean so they pathogens don't get out of hand.
Keeping clean and keeping the seahorses stress free should be sufficient.
It is hard to identify a seahorse that you don't know where it comes from and until it is adult but very clear side profile shots UP CLOSE can help.
Just to show you how hard it can be, check out this Guide to Identification of Seahorses.
It will probably take some time to fully load because of the size of the file.
For me, it takes 3 to 5 minutes to fully load, depending on time of day.
As for UV, that depends on who you ask because there are proponents and opponents for with or without.
I don't use them and never have in my 18+ yrs of reefing.
Uv is only going to get the pelagic stages of pathogens and algae and not even all of them at that, so you will always have pathogens present.
The key is to keep the tank very clean so they pathogens don't get out of hand.
Keeping clean and keeping the seahorses stress free should be sufficient.
It is hard to identify a seahorse that you don't know where it comes from and until it is adult but very clear side profile shots UP CLOSE can help.
Just to show you how hard it can be, check out this Guide to Identification of Seahorses.
It will probably take some time to fully load because of the size of the file.
For me, it takes 3 to 5 minutes to fully load, depending on time of day.