They don't really swim all that much... usually sit on the bottom or float around. I don't think they'd mind a short water column. A 1/2 full 10g is probably about as high as my 2.5g, and the frog does fine in there. Four frogs shouldn't be too many in about 5 gallons of water, as long as they're getting enough food. It's not like they need individual territories  .
__________________ 45g SW~percula clown, dusky jawfish, lubbock wrasse, antenna goby, hermits, snails
37g~angel, opaline gourami, australis rainbow, syno. euruptus, 6 kuhli loaches
10g~guppies, hoplo catfish, 3 kuhli loaches
5g~black CT betta |