I’m planning to provide not my paros but my Betta edithae with such “summer-resort”, too.
So up to now I placed a 250-litres tank in a half-shadowy place in our garden (not on teh ground but on a shelf) and started to fill it with fresh and used r/o-water (as I do not trust the rainwater I get from our roofs). As I have no car, this goes rather slowly.
Once there are about 15 to 20cm of water in the tank (= 75-100 litres), I’m going to add local marsh and water plants – and finally the fish. (In first place, I planned to do this with some Elassoma, but they are much to expensive for such a test and to small to observe them in such tank anyway. So now that I have the pretty strong Betta edithae swimming, this will be my “guniea pig”)
My concernes so far:
overheating during day + undercooling over night
– Solution so far: semi-shadowy place; tank covered; plenty of plants providing additional shadow
extreme evaporation without proper refill (in time of longer absence, i.e. vacation)
– Solution so far: tank covered with the standard cover, but leaving a vent for air circulation and for food to get in
leck of food (?) (in time of longer absence, i.e. vacation)
– no solution so far: As I don’t want to keep the tank uncovered, there might be too few insects finding the inlet. But actually, healthy adult fish should be able to easily live with such diet.
Now I would like to measure the maximum (and minimum) temperature during a 24-hour cycle. As there are cheap thermometers available that save the maximum level reached, this would be a good indication, whether or not additional shadow is needed.
Regarding the minimum teperature, I’m not as concerned: As it should not drop lower than 10 or 15°C (at least not for a longer period), this should be okay at least for my fish.
I guess, a good way to prevent at least overheating is to keep fish in half-buried barrels or basins with plenty of water lillies etc. covering the water surface. This seems to work pretty well with larger labyrinth fish such as Macropodus, Trichgaster or Trichpodis sepcies.
Anyway: I’m pretty interested in any field report, too! 🙂