I cannot decide between a merman or vampire and thought a mer vamp hybrid might be an interesting combination. I'm particularly drawn to the aqua vampire due to the water, swampy aspect but have read they are for experienced vampire keepers which im not. I was hoping anyone with a vampire hybrid could tell me a bit about there experiences please?

I had a call for a Vampire-Pleidian Hybrid once (a type of alien), but for various reasons we did not come together. In general I am not drawn to the hybrids for some reason. A Mer Vamp sounds lovely though. I do have an Aqua Vamp, and he is INTENSE and very predatory. Yes, for the advanced keeper!

Perhaps mamba mutu?:
https://cryptidz.fandom.com/wiki/Mamba_Mutu