Join Date: Sep 2006
Location: Northern Virginia
You might could get by with 5 or 6 female bettas in a 10 gallon tank. They do better either solo or in a group of 6 or more (so that the low one in the pecking order doesn't get beat all to hell by the alpha babe.)
As I mentioned in an eearlier post, one of the dwarf cory species might be the way to go.
Alternately, a microrasbora species might be good - they don't nip like tetras. If I were going to have any fish that were mid water swimmers, though, I'd make sure to put in some realy plants with bushy leaves, like hornwort, cabomba, rotala, or amubulia. Something that the smaller fish can hide in.
Bettas may or may not get along with shrimp. Everything I have read about it suggests that it's an idiosychratic thing for each betta. So I'd go with Amanos at the most expensive.
As for the filter, I have a 5.5 gallon betta tank (cycling - waiting for a good halfmoon betta to come into my LFS) with a Duetto 50 in-tank filter with the outflow pointed at the glass. Since it's a planted tank, I have taken the carbon insert out (and I am going to replace it with a second bio-sponge). It's keeping the water crystal clear. I had previously run it in a 10 gallon with a half dollar sized turtle, and it did a good job keeping that filtered until the impeller got gunked up. (The turtle is now the size of my palm - and I have big hands - and has a 75 gallon to itself with an Emperor 400, and I am going to be adding an Eheim 2217 to that as well.)
Logic is only the beginning of wisdom