I've got the sort of tank your looking at setting up, been running for about 5 months now
its an unknown kinda make, a sicce 4.3 gallon tank
currently houses 6 kuhli loach, 2 african drawf frogs, a male crowntail betta, 2 julie corys and one bronze cory, and a zebra snail
I used to have 3 zebra snails unfortunately the frogs decided they liked the look of them, so i wouldnt recommend snails
initially i started out with one frog, however he hid behind the filter box and rarely moved, since the addition of another he's become very sociable, and if my hands at the bottom of the tank picking out uneaten pellets they both hop into my hand
Its a silk plant aquarium, with fine gravel, and while people may think it's not the greatest size for the fish, they all seem very happy and i've had absolutely no problems with any of them.
My kuhli seem to be an exception, and don't really hide but prefer to chase each other around the plants, and they really do give me great pleasure to watch, hope my experiences can help you out