I am pretty experienced with freshwater setups, however I am new to saltwater. I have researched for hours, going on different forums, etc. But I still had some questions: I want to setup an eel tank, with only one eel. I have not decided between a zebra eel or a dragon eel, though I read both are rare and VERY expensive. Also, I need to know if this setup is good for a fully grown eel. I am planning on getting a 55 gallon tank with the eel being the ONLY fish (is this a good idea?). Is this large enough? Most websites say a minimum of 75 gallons, but I think they all assume you will have other fish as well. I heard from an employee at a specialty shop that the bioload of an eel is immense, often requiring oversized filtration just to compensate. Are freshwater filters the same as saltwater ones? For example, in my freshwater tanks I use a marineland power filter, is this okay for saltwater use? Also, the employee said it is an absolute must to get a protein skimmer, but is it okay if I use live rock and a power filter? Or is that not enough? And lastly, I was curious about actually adding the eel. After I am done cycling my tank, wont adding such a huge fish create a nitrogen spike that could potentially kill the eel and ruin my tank?