Hi my fish shop has freshwater moray eels on sale I really want one . I have a few questions. I know they are brackish then full salt. What do I need to measure the salt or how much salt per gallon .What size tank can I start with for say 8 in eel and what size will I eventully need my biggest is a 125 gal. Can I keep them with catfish if the catfish are bigger then it is . Thanks off to do some more reading.