ok, so the pet store i bought the 180 gallon from last week told me(i am a very frequent customer) that they had gotten some fish by mistake and they recieved two reticulated rays. they kept one for their 300 display tank, and they said they would sell me the other for $20. i have researched rays and know they arent good for a new tank, so they aggreed to hold it for a month or so until I can get mmy 180 set up and cycled. they are about 5-6 inches across, and seem to eat well. will the 180 be enough? i have been considering rays for a while, but was told my tank would be too small, but the store said that they would give it to someone else if i wasn't interested, and seeing as im about the only knowledgable fishkeeper who shops there, i can't bear the idea of some noob with a 30 gallon tank buying him. i am planning on building a 400 gallon tank sometime within a year, so will my 180 be enough for now? i know the requirements, and i was going to use sand substrate anyway, and the only bit of structure i have is a sort of driftwood stump that is sort of up on stilts, so that there is no part of the actual stump on the ground except about five stilt like structures. this is stable, i have had it in a tank before, and if i put a piece of slate under it and cover that with sand, then would that work? this ray is too good to be true. help me here!