OohFeeshy
It's only forever; not long at all...
Mm, substrate would most likely be something soil-ish- based on both appearance (puddles) and 'clear unless roiled', implying there's a stirr-uppable sediment.
i personally would say a dark sand.
they lived in lakes/pools so it will more than likey be a dark coloured base.
ill find a few articls sites for you in a second
i wouldnt use pea shingle imo. will look to big with such a small fish.
personally i would use a dark sand (as said above) and have few small pieces of wood. i would plant about 50% of it.
How about no sand at all, i've found that soaked coconut fibre (used as a substrate in terraniums for tarantulas and the like) makes a great substrate for puddle type biotopes which would naturally have a thick layer of mulm on the bottom, though it would mean having to plants the plants in pots.
please don't say from a coconut 
Any pet shop that sells reptiles will have coconut fibre, you buy it in compressed blocks which have to be soaked in a bucket of water for a few hours to break up, its not expensive either.
good call CFC! i never thought about using that! i may give that a try some day!Any pet shop that sells reptiles will have coconut fibre, you buy it in compressed blocks which have to be soaked in a bucket of water for a few hours to break up, its not expensive either.
How about a mix of dark and normal sand, I find the black sand too severe really