Hi welcome to AA
I really think it is best to start with FW
tanks. Less can go wrong, you can keep more fish, it's MUCH cheaper, etc. But, some people have started with SW
, then moved on to FW
Ever since I was little, I have loved deap sea SW
fish, but I knew I couldn't keep them just then. When I had the chance to start a small FW
tank (even though I didn't research and killed everything eventually) jumped on it! It wasn't my dream tank, but just a few months later I have my new, cycled, 25 gallon planted. I am in love! There are so many cool and interesting fish you can keep in FW
tanks too. Just letting you know how addicting this hobby is: I am starting at least 2 more tanks at the beginning of next month. For sure a 12 gallon long brackish planted bumblebee goby tank, (That's a mouth full!) and a 5.6 gallon planted dwarf puffer tank. I am also hoping to have a 5-10 gal
shrimp tank, a 5 or so gal
betta, and a 5 gal
Pygmy Sunfish tank, all of which are fw
I will tell you, if I ever do a SW
tank, it will be a 40 breeder tank with pred fish like an angler.
But back to your question, and sorry for my rambling
Sting rays will be harder to find a pretty expensive. I do know you can keep freshwater sting rays. But if you can get SW
ones, go for it! You will need a HUGE tank for them. Like, HUGE
If you want to have a huge reef, which it sounds like you do, I hope you have a well paying job! You are going to need massive lights, massive amounts of live sand and rock, not to mention other equipment. Fish, corals, CUC (clean up crew) etc, it's going to cost a lot. But if you do this, I will be with you all the way!
I just re-read your statement, and you want to have a small reef tank. Say, 20 gallons. That would still be fun, and still cost quite a bit!
All I can tell you is: read, read, read, and read some more, then some more, and a little more. Then wait until some salties come over here and help you