If it were me, I'd put a 5cm layer of gravel or sand at the bottom and plant twisted Val or similar with java fern attached to wood a long piece of driftwood. A canister filter will be a bit of an eyesore but placing the spray bar vertically at one end and the intake at the other would give decent flow. As for fish, I'd go for a large (40-50) shoal of neons or red phantoms.