small Paludarium fish species

A dwarf puffer would be fine, if you had them be the only fish in the tank.

Any other way, and you could mix and match types of small fish to your liking.
 
Some small danios or even endlers livebearers may work in there.

Also, light passing through 'air' meets much less resistance so limiting the depth of water based on light may or may not be necessary... I have read that any distances less than 2 feet can be considered negligible for calculating light intensity. Granted 30" is a little more than that...

I have otocinclus cats in two of my tanks... I'm not sure what they are eating but I don't really do anything extra for them... there is no shortage of some types of algae that they are known to eat (softer ones in my experience) so maybe I have struck a balance with the number of otos to the amount and rate that algae grows... the live plants may also make a difference (?)
 
I would worry about the puffer biting at frogs that come into the tank area, tho mostly puffers can live w/ ottos.
 
is there going to be a filter in the water? air pump with carbon? small water pumpand floss/carbon filter for a water fall in the upper section? a golden picostomus wil do the job for algea and he will eat just about anything the driftts to the bottom in stores available at 2" max sixe is only 6" but that would take a couple years. if you realy want some fish that will work well in a shallow water set up look at a fish call agoo-boo's but there not cheap look on aqua bid.com or maybe bublebe gobies or desert gobbies i'd stay away from neons never keeping fish before i'd doubt they'd live long. look more at blood fin tetras, greenflame tetra or maybe harliquin rasboras. guppies would wouk but i can't see them with dart frogs.
 
AquariaCentral.com