Hi Aleksandr. The tank is 25 litres (perhaps a little small for 2 pairs, but will do for now). The filter is what was in the tank already – a Dennerle ‘Eckfilter’, I have simply passed the outflow through the foam to create a mattenfilter, providing a large surface area for filtration, moss growth and perhaps microfauna. Already the fish seem to spend quite some time grazing on it.
Water stats are currently pH 5.6, 90µs and 24 degrees. I started the fish in tap water (as at the fish shop) and am performing frequent small water changes with RO to bring the numbers down gradually.