How big can I go while keeping the same light?

[OCDP]

Yikes. Back to the drawing board???

The more I read your post the more angry I get that the LFS told me its okay in a 20g. I wouldn't have expected this from them. What a shame... then again, I am just as much to blame, I should have done more research.

So a cube isnt going to work basically is what yoru saying Bev.. I need something long... bottom line.

Well, if this is the case , then perhaps this fish won't be able to stick with me The longer I go, the worse its going to be.. this is in my bedroom where space is very limited.